Conversion
Conversion Calculators
Convert a quantity from one unit into another, and see the factor that did it. Most of these conversions are exact by definition rather than measured — an inch is 25.4 millimetres exactly, a pound is 0.453 592 37 kilograms exactly — so each tool shows that defining constant instead of a rounded decimal, and a result can be checked by hand. Where a conversion is not a pure ratio, the page says so plainly: turning a volume into a weight needs a density, turning a mesh number into microns needs a named sieve standard, and a US gallon is a fifth smaller than an imperial one under the same word — a converter that hides those inputs is returning a number it cannot justify. The exact-versus-derived distinction, and the rounding each unit deserves, are treated here as part of the answer rather than a footnote.
Number Systems
Volume
Length
Weight
Temperature
Area
Speed
Pressure
Data
Energy
Power
Angle
Density
Fuel
Torque
Digital
Geographic
Weather
Land
Kitchen
Sizing
Screen
Geometry
Acoustics
Workshop
Automotive
Electrical
Engineering
Physics
Concentration
Notation
Text
Who this is for
Built for anyone who has to restate a quantity in someone else’s units: a reader working out what “₹2,400 crore” means in dollars, an engineer moving between psi and bar on a spec sheet, a contractor turning cubic yards of aggregate into the tonnage a supplier will actually deliver, a cook converting a weight into a spoon measure, and anyone who has typed a conversion into a search box and wanted to see the factor rather than just the answer.
How to choose a calculator
Twenty-one tools here so far, and they answer different questions. Open the Volume Converter for litres, gallons, pints, quarts, cups and cubic units — it keeps the US and imperial measures apart, which matters more than it sounds: a gallon is about 20% larger in imperial measure, and a fluid ounce is about 4% smaller, so the two systems disagree in opposite directions under the same two words.
The Length Converter and the Weight Converter cover the other two everyday dimensions. Length is the straightforward one — a single 1959 agreement fixed the inch at exactly 25.4 mm, so there is no US-versus-imperial split to navigate — and its trap is the mil, a thousandth of an inch rather than a millimetre. Weight’s trap is the ton: short, long and metric are three different masses sharing one word.
For large numbers there are two pages, and they solve opposite halves of one problem. The Million, Billion and Trillion Converter handles the case where two conventions use the SAME word for different numbers — a German or French billion is a US trillion — and warns you when the name you picked is one of those. The Lakh and Crore Converter handles the case where they use DIFFERENT words, which is the easier failure to notice and the harder one to compute, since there is no international name for a lakh at all.
The Temperature Converter is the one that does not behave like the others. Every other page here multiplies by a constant; temperature scales carry an offset too, which means a reading and a CHANGE convert differently — 20 °C is 68 °F, but a rise of 20 °C is a rise of 36 °F. It asks which you mean rather than assuming, because assuming is how a delta-T becomes a wrong number that still looks like a temperature.
Three more cover the rest of the everyday dimensions, and each has its own trap. The Area Converter squares the factors for you, because a metre is 3.28 feet while a square metre is 10.76 square feet. The Speed Converter explains why running pace is not a speed unit at all but its reciprocal, moving the opposite way. And the Pressure Converter is about the question no factor answers: whether your reading was gauge or absolute.
The Data Storage Converter carries decimal and binary units under their real names — kB against KiB, GB against GiB. That distinction is why a 1 TB drive shows as 931 GB: the drive holds 1012 bytes exactly as sold, and the operating system divides by 230 before writing the decimal label on the result.
The Energy Converter covers food, electrical and heating energy together, and carries the two calories apart: a small calorie is 4.184 J, while the Calorie on a nutrition label is a kilocalorie — a thousand of them. A capital letter is a fragile thing to hang a factor of a thousand on, which is why most of the world writes kcal instead.
The Power Converter repeats the ton problem in a place people meet far more often: a 150 PS German car is 148 hp in Britain, because metric and mechanical horsepower differ by about 1.4%. And the Angle Converter is the one page here whose factors are not exact — π is irrational — which it says rather than hides, alongside the reason a spreadsheet’s SIN(90) returns 0.894 instead of 1.
The Volume to Weight Converter is the deliberate exception to all of it. Turning gallons into pounds is not a unit conversion at all — a gallon of petrol weighs 6.2 lb, of water 8.3 lb and of honey 11.9 lb — so it asks which substance, and answers with a realistic range instead of a single figure that a load of gravel could never actually have.
The Roman Numerals Converter has no factors at all — it transcribes between two ways of writing the same whole number. It reads the older spellings you actually meet, such as the IIII on a clock face, and answers with the standard modern form; and it refuses zero, negatives and fractions rather than inventing notation the system never had.
The Fuel Economy Converter is the only one here whose units run in opposite directions: mpg is better when higher and L/100 km when lower, because they are reciprocals rather than scalings. It also keeps US and UK mpg apart — a British 40 mpg is a US 33.3 — and shows why a 5 mpg gain at the bottom of the range saves more fuel than a 20 mpg gain at the top.
The Numeral Base Converter shows the relationship rather than only the answer: four bits is exactly one hex digit, so converting between them regroups the bits and moves no arithmetic at all. It also asks for a width before writing a negative, because −5 is 11111011 at 8 bits and 1111111111111011 at 16.
The Torque Converter exists mostly for one mistake: inch-pounds and foot-pounds differ by twelve and both appear on the same vehicle’s specifications, so a sensor specified at 100 in·lb and tightened to 100 ft·lb is twelve times over-torqued. It also declines to convert torque into energy, which would be easy and wrong.
The Colour Converter goes past the format change to the question behind it: whether text on that colour will be readable. The WCAG threshold is sharper than it looks — #767676 passes on white and #777777 fails — so it is computed rather than eyeballed.
The Coordinates Converter exists for a failure that hides itself: 40° 26′ 46″ N is 40.4461° and the digits read straight across give 40.2646°, about 20 km away — and since that is also a valid latitude, nothing downstream can tell it is wrong. The tool works the distance out from your own coordinate.
The Text Case Converter is the one with no arithmetic at all. It shows every case style together, because “title case” is at least three different rules, and it warns when your text lower-cases differently under Turkish rules — the difference that breaks a case-insensitive login for someone typing their own name correctly.
Open the Lakh and Crore Converter to move a figure between the Indian system (thousand, lakh, crore, arab) and the international one (thousand, million, billion, trillion), in either direction. It also does the two things that make an Indian figure readable rather than merely correct: the 2,2,3 comma grouping that writes ten million as 1,00,00,000, and the same amount spelled out in words.
Neither is an estimate. Every factor in this category is exact by definition — an inch is 25.4 mm, a US gallon is 231 cubic inches, a lakh is a hundred thousand — and the arithmetic runs on exact rationals rather than floating point, so the only rounding is the number of decimal places on screen.
Compare conversion calculators
What each calculator is best for, the main inputs it needs, what it shows, and what to keep in mind.
| Calculator | Best for | Key inputs | Shows | Keep in mind |
|---|---|---|---|---|
| Text Case Converter | Headlines and identifiers, where the styles genuinely differ | Any text — a headline, a variable name, a paragraph | Every case style at once, including three separate title-case styles, with word and character counts | No automatic case can know your proper nouns, and case conversion is locale-dependent — the tool flags text that lower-cases differently in Turkish |
| Coordinates Converter | Coordinates copied from a document, where the digits look like a decimal | Degrees, minutes, seconds and a hemisphere — or a decimal figure, for latitude or longitude | Both notations, plus a live figure for how far the digits-run-together misreading would land you from the real point | A coordinate needs a datum as well as numbers, and this page assumes none — the same point differs by about 100 m between OSGB36 and WGS 84 in Britain |
| Colour Converter | Picking a colour that text will actually be readable on | A hex code in three or six digits, with or without the hash, or an rgb() value | Hex, RGB and HSL together, plus the WCAG contrast ratio against white and black with a plain pass-or-fail verdict | A contrast ratio is a floor rather than a target — it does not model font weight, and it does not flag pairs that are specifically hard for colour-blind readers |
| Torque Converter | Fastener specs, where in·lb and ft·lb sit on the same sheet | A torque figure and the unit it is in — N·m, pound-feet, pound-inches, ounce-inches or kgf·m | Every torque unit at once, with the twelve-fold pair named apart rather than left to be read carefully | Refuses to convert torque into energy despite identical dimensions. And a converted figure cannot carry the spec’s conditions — a thread lubricated where the spec said dry gains 20–30% clamping force at the same reading |
| Numeral Base Converter | Byte dumps, permissions and colour codes, where hex and binary are the same bits | A value and the base it is written in — binary, octal, decimal, hex, base 32 or base 36; plus a width when the value is negative | Every base at once, with the 4-bit grouping that maps binary onto hex shown rather than asserted | A negative has no binary form without a width, and a value outside that width’s signed range is refused rather than wrapped into a valid encoding of a different number |
| Fuel Economy Converter | Comparing a car quoted in one market against one quoted in another | An economy figure and the unit it was quoted in — US mpg, imperial mpg, km/L or L/100 km | Every unit at once with the better direction labelled, the fuel used over 15,000 miles, and a table showing why small mpg gains beat large ones | The conversion is exact but the label figure is a test-cycle result — European figures moved from NEDC to WLTP and read 10–20% worse for the same car |
| Roman Numerals Converter | Years on cornerstones and credits, regnal numbers, and clock faces | A whole number from 1 to 3,999, or a numeral — including older spellings such as IIII | The number and its standard modern numeral side by side, with a reference table generated by the same engine | Refuses zero, negatives, fractions and anything above 3,999 rather than inventing notation — the system genuinely has no symbols for them |
| Volume to Weight Converter | Fuel, aggregates and ingredients, where the substance decides the answer | An amount, the volume and weight units, and — the part that makes it answerable — which substance it is | A typical figure alongside the realistic low-to-high range, with the reason for that range stated on the result | The only tool here whose answer is not exact. Densities move with moisture, compaction and grade, so this is for planning — a load that will be paid for should be weighed |
| Power Converter | Comparing an engine or appliance rating quoted in another market’s units | An amount and the unit it is in — watts, kilowatts, mechanical horsepower, metric horsepower or BTU per hour | Both horsepower listed apart, alongside the metric scale and the BTU/h used for heating and cooling capacity | The factors are exact but a RATING is not — pre-1972 SAE gross figures read about 20% high, and volt-amperes are not watts unless the power factor is 1 |
| Angle Converter | Trigonometry and coordinates, where degrees and radians get mixed up | An amount and the unit it is in — degrees, radians, gradians, turns, arcminutes or arcseconds | Every angle unit at once, with the π-based factors flagged as approximate rather than defined | These are the only inexact factors on the site, because π is irrational — and a spreadsheet’s SIN() takes radians, so SIN(90) returns 0.894 rather than 1 |
| Energy Converter | Nutrition labels and utility bills, where “calorie” means two different things | An amount and the unit it is in — joules, small calories, food Calories, watt-hours, BTU or therms | Food, electrical and heating energy in one list, with the small calorie and the food Calorie carried apart rather than merged | Energy is not power — converting one into the other throws rather than guessing. And a label Calorie is a measurement of the food, not of how much of it you absorb |
| Data Storage Converter | Capacity figures, where a “GB” may mean 10⁹ bytes or 2³⁰ and the label does not say | An amount and the unit it is in — bits and bytes, decimal kB to PB, and binary KiB to PiB | Both prefix systems at once under their real names, so the gap between them is visible rather than assumed | Both systems are exact — the difference is a definition, not a discrepancy. Formatted capacity is a separate reduction again, and RAM is genuinely binary |
| Area Converter | Floor and land area, where reaching for the length factor is a threefold error | An amount and the unit it is in — square units, acres, hectares, ares and the cent | Every area unit at once, with factors derived by squaring the exact length factors rather than stored separately | Carries only land units with one settled definition — the bigha, katha and gunta genuinely differ by Indian state, so no national figure is offered for them |
| Speed Converter | Speed limits abroad, and any figure quoted in knots | An amount and the unit it is in — mph, km/h, m/s, ft/s or knots | Every speed unit at once, with the nautical mile behind the knot explained rather than assumed | Pace in minutes per kilometre is a reciprocal rather than a speed unit and is deliberately not offered here; average speed is also not the mean of the speeds along the way |
| Pressure Converter | Tyre, hydraulic and process pressures, where psig and psia are 14.7 psi apart | An amount and the unit it is in — psi, ksi, bar, kPa, MPa, atm, torr, mmHg or kgf/cm² | Every pressure unit at once, with the torr and the millimetre of mercury carried separately rather than merged | Gauge and absolute pressure differ by an offset, not a factor, so no conversion bridges them — the tool says which question is which rather than inventing a local atmospheric pressure |
| Temperature Converter | Any delta-T or “warmer by” figure, where applying the offset gives the wrong answer | A number, the scale it is on, and whether it is a reading or a change — the mode is a deliberate choice rather than a hidden default | Celsius, Fahrenheit, kelvin, Rankine and Réaumur at once, in either mode, with the reading-versus-change contrast shown side by side | Refuses a reading below absolute zero rather than returning a number — and a ratio of Celsius readings is meaningless, so 40 °C is not twice as hot as 20 °C |
| Million, Billion and Trillion Converter | Reading a large figure when the source did not say which convention its “billion” follows | An amount and the scale name it was written as, chosen from the short-scale or long-scale list | Both naming conventions side by side, the full figure in grouped digits and in words, and a warning when the name you picked means a different number elsewhere | Exact arithmetic, but no tool can resolve an ambiguous source — if a document says “billion” without stating its convention, the date, language and publisher are the evidence, not the number |
| Length Converter | Metric and imperial length, including the units that get mistaken for each other | An amount, the unit it is in, and the unit you want — nanometres through nautical miles | Every length unit at once, with the mil (thou) labelled apart from the millimetre and the nautical mile apart from the statute mile | Exact by definition since 1959, but gauge and sieve-mesh numbers are defined by named standards and are not a length conversion at all |
| Weight Converter | Any mass figure where the word ton or stone needs pinning down | An amount, the unit it is in, and the unit you want — micrograms through tonnes, plus ounces, pounds and stone | Short ton, long ton and tonne as three separate units, alongside the metric scale and the imperial one | Converts mass, not force — and a mass ounce is not a fluid ounce; crossing to volume needs the density of the specific substance |
| Volume Converter | Reading a volume off a source that did not say whose gallon it meant | An amount, the unit it is in, and the unit you want — with US and imperial listed as separate options rather than one shared name | Metric, US customary and imperial volume at once, including cubic inches, feet and yards, plus a side-by-side table of the four units that share a name across the two systems | Exact by definition, but it converts volume only — turning a volume into a weight needs the density of the specific substance, and cooking cups are a family of conventions rather than one standard |
| Lakh and Crore Converter | Reading a figure quoted in lakh or crore when you think in millions, or the reverse | A number, and which system it is written in — Indian (thousand, lakh, crore, arab) or international (thousand, million, billion, trillion) | The same quantity in both systems at once, the Indian 2,2,3 comma grouping alongside the international 3,3,3 one, the amount written out in words, and a reference table from one lakh to one lakh crore | Exact by definition, so the arithmetic cannot drift — but it converts scale only, never currency; a rupee figure still needs a dated exchange rate applied separately |
Best calculator path
- Enter your figure and pick the scale it is written in — Indian or international. The other side updates as you type.
- Compare the two systems place by place to see exactly where they diverge, which is at a hundred thousand and never realigns.
- Check the comma grouping. Indian notation groups the last three digits and then in twos, so the familiar 10,000,000 becomes 1,00,00,000.
- Use the reference table for the values that come up most in reporting, from one lakh to one lakh crore.
Common mistakes and limits
- Treating a crore as ten million. It is ten million only in the sense that both are 107; the trap is the step below, where a lakh is a hundred thousand and there is no international word for it, so a figure read place-by-place drifts by a factor of ten.
- Carrying international commas into an Indian figure. Writing a crore as 10,000,000 is arithmetically fine and typographically wrong in Indian usage, where it is 1,00,00,000 — and a reader scanning for the comma pattern will misread the magnitude.
- Assuming “billion” is stable. The short-scale billion (109) is now standard in English-language finance, but older British and several European usages put it at 1012. When a source is old or translated, check which one it means before converting.
- Converting currency and scale in one step. A figure in crore of rupees needs the scale conversion and an exchange rate, and the exchange rate is a moving number with a date attached. Do them separately so it is clear which part is exact and which is a rate on a particular day.
When not to rely on calculators alone
A conversion is only as good as the unit it started in. The arithmetic on this page is exact, but it cannot tell you whether the source figure was a lakh or a lakh crore, whether a quoted tonne was metric or a US short ton, or whether a spec sheet’s psi was gauge or absolute — and each of those mistakes changes the answer by orders of magnitude while every digit on screen stays plausible. Read the unit from the original document rather than from a summary of it. For anything that carries legal or commercial weight — a contract value, a customs declaration, a dosage, an engineering sign-off — confirm against the source document and the governing standard, not against a converter.
Source and calculation basis
These are definition-based tools with no external data feed: every figure is computed from what you type, using conversion factors that are fixed by definition rather than measured. The Indian scale names and the 2,2,3 grouping convention follow standard Indian usage as set out in Indian government and Reserve Bank of India publications, which quote figures in lakh and crore as a matter of course. Where a future tool in this category depends on something that is not a defined constant — a material density, a sieve standard, a hardness scale — that dependency is stated on the page itself and the governing standard is named, because a derived factor and a defined one deserve to be told apart.
See the Methodology for how calculators are built and reviewed, who runs the site, the Disclaimer for the full terms, and the Contact page to report an issue.
Frequently asked questions
Common questions about conversion calculators and how to use them.
What calculators are in the Conversion section?
Twenty-one so far. The Volume Converter handles litres, gallons, pints, quarts, cups and cubic units, with the US and imperial measures labelled apart rather than merged — a gallon is about 20 per cent larger in imperial measure, while a fluid ounce is about 4 per cent smaller, and a converter offering one unnamed gallon is silently wrong for one of its two largest audiences. The Lakh and Crore Converter moves a figure between the Indian number system (thousand, lakh, crore, arab) and the international one, formats it with the Indian 2,2,3 comma grouping, and writes it out in words. The Length Converter runs from nanometres to nautical miles on the 1959 factors, and keeps the mil — a thousandth of an inch — clearly apart from the millimetre. The Weight Converter lists the short ton, long ton and tonne as three separate units, because they are three different masses differing by up to 12 per cent under one word. The Million, Billion and Trillion Converter handles the harder version of the same problem the lakh and crore page solves: there, two systems use different words, so a reader knows a translation is needed; here both use the SAME word for different numbers, since a German or French “Billion” is a US trillion. The Temperature Converter is the odd one out: temperature scales carry an offset as well as a factor, so a reading of 20 °C is 68 °F while a RISE of 20 °C is a rise of 36 °F — a distinction almost every converter omits, and one that quietly corrupts every delta-T. Area, Speed and Pressure complete the everyday set, and each owns its own failure rather than repeating the pattern: area is where a length factor must be squared, speed is where pace turns out to be a reciprocal rather than a unit, and pressure is where gauge and absolute differ by an offset that no factor can bridge. The Data Storage Converter answers the question that dimension is actually asked — why a 1 TB drive displays as 931 GB — and the answer is that two exact systems share one vocabulary rather than that anything is missing. The Energy Converter separates the small calorie from the food Calorie, which is a thousand times larger and distinguished on a US label only by a capital letter. Power carries both horsepower — mechanical and metric differ by 1.4% under one word — and Angle carries the only approximate factors here, because π is irrational and everything else in the category is exact by definition. The Volume to Weight Converter is the deliberate exception to everything above: it is the only one whose answer is a range rather than an exact figure, because volume and weight are bridged by density, which belongs to the substance and not to the units. The Roman Numerals Converter has no factors at all, being a transcription between two ways of writing one integer, the Fuel Economy Converter is the only one whose units are reciprocals of each other — a better car has a higher mpg and a lower L/100 km — the Numeral Base Converter shows that hex is not a rival system to binary but the same bits grouped four at a time, the Torque Converter refuses to turn a pound-foot into a joule even though the two are numerically equal, because torque and energy are different quantities that happen to share a dimension, the Colour Converter adds the contrast ratio to the format change since that is usually why a hex code was being looked up at all, the Coordinates Converter shows how far the commonest coordinate misreading would put you — about 20 km, from a value that is itself a perfectly valid latitude — and the Text Case Converter shows three title-case styles at once, because Chicago, AP and a word-boundary regex genuinely disagree. Thirteen of the fifteen run on factors that are exact by definition. More are planned across data, energy and the conversions that need a density or a named industry standard, plus the conversions that need a density or a named industry standard rather than a fixed factor.
Why does a converter need a whole category when phones and search boxes already convert units?
For the simple cases it does not, and that is said plainly: if you want centimetres in inches, your search box answers instantly and these pages are not trying to beat it. The tools here exist for the conversions that a one-line widget cannot do honestly. Turning a volume into a weight needs the density of a specific substance. Turning a sieve mesh number into microns needs a named standard, and the standards disagree. Reading a figure quoted in crore needs a number system that most converters do not implement at all. Those are the cases where showing the assumption matters more than showing the answer.
Are the conversion factors exact or rounded?
Most are exact by definition rather than measured, and each page shows the defining value it used. An inch is exactly 25.4 millimetres, a pound is exactly 0.453 592 37 kilograms, and a nautical mile is exactly 1 852 metres — these are definitions agreed by treaty, not measurements with error bars. So the arithmetic carries no uncertainty, and where a result differs from another tool it is a rounding or display decision rather than a disagreement about the factor. The exceptions are flagged on the pages that have them: anything depending on a density, a temperature, or a named industry standard is derived rather than defined, and is presented as such.
Why is a lakh and crore converter here rather than in the Math section?
Because the intent is transcription, not calculation. Someone converting 250 crore to billions is reading a figure written in one convention and needs it in another; no mathematics is in question and the underlying quantity never changes. The Math category owns operations performed on numbers — percentages, algebra, statistics. Conversion owns restating the same quantity in a different unit or notation, which is a different question even when both are arithmetic underneath.
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