Working from money invested rather than quantity held
Nobody thinks in eight decimal places. The natural question is what a given sum put in at a given price is worth today, so this derives the quantity for you — the money invested, less the entry fee, divided by the price paid.
BTC held = (amount - fee) / buy price ; value = BTC held x current price
That fee deduction matters at the front. Taking the fee off before converting to coins is what an exchange actually does, and skipping it slightly overstates the position from the first day onward.
Why the percentage is lower than the price change
The return here compares the current value with the full amount invested, including the fee. So if the price doubles and you paid 1% to enter, the return is not 100% — it is closer to 98%, because part of your money never bought any coins.
That is the honest measure. Reporting the return against the post-fee amount flatters the result by quietly excluding a cost you genuinely paid.
The number is true for one price, and that price moves
This values the position at whatever current price you enter. Bitcoin has repeatedly moved by double-digit percentages within a single day, so a figure computed this morning can be materially wrong by the evening.
It also says nothing about the path. Two positions showing the same return today may have had entirely different drawdowns along the way, and the deeper one was considerably harder to hold.
Exit costs, custody, and the tax that is not modelled here
The current value is an unrealised figure. Selling costs a fee on the way out, and moving coins between wallets or off an exchange costs network charges that scale with congestion rather than with your position size.
Tax is not applied. Most jurisdictions tax a disposal, several at rates specific to crypto, and a few disallow offsetting losses against other gains — so the after-tax result on a realised position can be considerably below the number here.
Frequently Asked Questions
How do I calculate my bitcoin return?
Find how much BTC you hold by taking the amount invested, subtracting the fee, and dividing by the buy price. Multiply that by the current price for the value, then subtract what you put in to get the profit. The calculator does this for you.
Does this tool forecast the bitcoin price?
No. The current price is a number you enter, and the calculator simply applies it. There is no prediction or recommendation here. Bitcoin is highly unpredictable, so any price you use is an assumption.
Why does the fee change how much BTC I hold?
The fee is taken from your cash before any coins are bought, so less money is actually converted to bitcoin. A 0.5% fee on 5,000 leaves 4,975 to buy with, which means slightly fewer coins.
Can I use it for a price I expect in the future?
You can type any current or hypothetical price to see a what-if value, but that is a scenario, not a forecast. The result only holds if the market actually reaches that price, which is never certain.
Is the return before or after tax?
Before tax. Capital gains rules vary by country and change over time, so the profit shown is pre-tax. Check your actual liability with a tax professional.
What happens if the current price is below my buy price?
The calculator returns a loss, shown as a negative profit and a negative return. This is a routine outcome for a volatile asset and a reminder that you can lose money, including your whole investment.
Does it work for other coins?
The maths is identical for any single-asset crypto position, so you can use it for other coins by entering that coin price as the buy and current price. Volatility and risk apply just the same.
Why is past performance not a guide?
Crypto prices are driven by sentiment, liquidity, regulation, and many other shifting factors. A strong run in the past does not make future gains more likely, which is why this tool avoids any forecast.
Sources & References
Figures on this page are checked against primary, authoritative sources. Links open in a new tab.
Returns are assumptions, not guarantees. Actual results may vary because of market performance, taxes, fees, inflation, and timing. This is an educational projection, not investment advice.
Published the calculator with its formula, worked example, assumptions, limitations and a bespoke guide, and added an automated formula test suite covering it.
Tested the quantity derived from the amount invested net of fee, and the current value and return that follow from it.
Tested that the return is measured against the full amount invested including the fee, not the post-fee amount.
Frequently Asked Questions now show on the page: 8 answers, checked in a page-by-page audit.
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