Math calculator

Days Calculator

Count the days between two dates, add or subtract days from a date, or count business days excluding weekends and holidays — with a full calendar breakdown and unit conversion to weeks, hours, minutes, and seconds.

Days between two dates Add or subtract days Business days & holidays Leap-year aware Free, no signup
Calculate days How it works

Free, no signup — verify anything used for a legal or payroll deadline.

Pick a mode below: the total days between two dates, a date plus or minus a number of days, or business days excluding weekends and holidays. Every result also shows a calendar (years/months/days) breakdown, not just a raw day count.

Enter your dates

Total days

0

Calendar breakdown

0y 0m 0d

Weeks

0 + 0d

Hours

0

Minutes

0

Seconds

0

Wednesday to Wednesday · no leap day in this range.

At a glance

Formula shown
Days between = (later date − earlier date), converted from calendar dates to a single day count.
Scenario support
Between two dates, add/subtract days, and business days excluding weekends and a custom holiday list.
Workbook export
CSV export (opens in Excel or Google Sheets)
Educational estimate
Planning support from the values you enter — not professional advice.

How to read your result

The total-days figure and the years/months/days calendar breakdown can both be correct and still look like different answers — 47 days is also "1 month and 16 days," and neither is wrong, they just answer different questions. By default the end date is not counted as an extra full day (a Monday-to-Thursday span is 3 days, matching 3 nights); switch on the inclusive option if your situation calls for counting the end date itself, such as "how many days was I on this trip." For scheduling and deadlines, decide up front whether you need calendar days or business days — the gap between the two grows fast once holidays are involved, since a 10-calendar-day window can be as few as 6 or 7 business days depending on where the weekends fall.

How the calculation works

Days between two dates

Days = (Later date − Earlier date) in whole days

Computed from calendar-day counts, so leap years are handled automatically.

Add or subtract days

Result date = Start date + N days

N can be negative to subtract instead of add.

Business days

Business days = Calendar days − weekends − holidays

Only Saturdays, Sundays, and listed holidays that fall on a weekday are removed.

Worked example

January 15, 2026 to March 3, 2026. That is a total of 47 days, or 1 month and 16 days on the calendar breakdown — the same span, two valid ways to state it. As weeks, it is 6 weeks and 5 days; as hours, 1,128.

Business days over the same span. Of those 47 calendar days, 13 fall on a Saturday or Sunday, leaving 34 weekdays. If a public holiday (say, a single Monday) sits inside the range, the business-day count drops to 33 once it is added to the holiday list.

Assumptions

  • All dates use the standard Gregorian calendar, with leap years applied automatically (a year is a leap year if divisible by 4, except century years not divisible by 400).
  • Calculations are date-only — no time-of-day component — so "days between" treats each date as spanning the whole day.
  • Business Days mode treats Saturday and Sunday as the weekend; it does not adjust for countries where the weekend falls on different days.
  • Holiday exclusion only removes dates you explicitly list — there is no built-in regional holiday calendar.

Limitations

  • Does not know public holidays automatically for any country, region, or company — you supply the list in Business Days mode.
  • Does not adjust for a Friday/Saturday (or other non-Saturday/Sunday) weekend used in some countries.
  • Not a substitute for the specific counting method (calendar days vs. business days, inclusive vs. exclusive) required by a legal document, contract, or payroll system — confirm that separately.
  • This is an educational and planning tool, not legal, payroll, or professional advice.

Frequently asked questions

How do I calculate the number of days between two dates?

Convert both dates to a single day count (days since a fixed reference point) and subtract the smaller from the larger. This calculator does that conversion for you and also breaks the result into a calendar years/months/days figure, since "47 days" and "1 month and 16 days" answer different questions from the same two dates.

Does this account for leap years?

Yes. The day-count math is date-object based, not a fixed 365-day-per-year approximation, so any February 29 that falls inside your range is counted correctly and flagged in the result.

Can I add or subtract days from a date?

Yes — switch to Add / Subtract Days mode, enter a start date and a number of days, and it returns the resulting date and its day of the week. Enter a negative number to subtract instead of add.

What is the difference between calendar days and business days?

Calendar days count every day, including weekends. Business (working) days count only Monday through Friday, which is what most payroll, shipping, and legal-deadline calculations actually use. Use the Business Days mode for that count.

Can I exclude public holidays from the business-day count?

Yes — list the holiday dates (one per line or comma-separated) in Business Days mode and any of them that fall on a weekday within your range are subtracted from the count. This calculator does not know regional holidays automatically; you supply the list.

Does this include or exclude the end date?

By default the end date is not counted as a full extra day (the difference between the two dates). Check "Count the end date as a full day" in Between Two Dates mode if you want an inclusive count instead — for example, a 3-night hotel stay checking in Monday and out Thursday is a 3-day difference, but "how many days was I there" is sometimes counted as 4.

Can I calculate days until a future date, or days since a past date?

Yes — that is Between Two Dates mode with "today" as one of the two dates. Set the start date to today and the end date to your target, or use the "Use today" shortcut next to the end-date field.

Can I convert days to hours, weeks, or years?

Yes — Between Two Dates mode shows the same span as weeks, hours, minutes, and seconds alongside the day count, and the calendar breakdown gives you the years/months/days figure directly, without a separate unit-conversion step.

Can I export the result to Excel?

Yes — Between Two Dates mode has a CSV download of the full breakdown, which opens directly in Excel or Google Sheets.

Is there a days calculator app I can download?

No — this is a free web calculator, not a downloadable app. It works the same in any browser on desktop or mobile, with no installation or account required.

Does this calculate astrology or numerology date compatibility?

No — this tool does plain calendar arithmetic (day counts, adding/subtracting days, business days). It does not calculate astrological or numerological compatibility between dates.

Does this calculate a pregnancy due date or fertile/ovulation window?

No — pregnancy and ovulation dating use specific medical estimation methods (based on last menstrual period and cycle length) that are a different calculation from general date arithmetic, and this calculator does not model them.

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Educational use disclaimer

This days calculator is for educational and everyday planning use only. It is not legal, payroll, contractual, or professional advice. Business-day results depend entirely on the holiday dates you enter — it does not know regional or company-specific public holidays automatically. For legal deadlines, contract terms, or payroll calculations, confirm the required counting method (calendar days vs. business days, inclusive vs. exclusive) with the relevant document or a qualified professional.

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Authorship & verification

Written and maintained by

  • Formula and examples verified on 5 August 2026
  • Educational estimate only

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