₿ What if you invested in Bitcoin?
← Curious CalculatorsThat $100 you almost invested. The $1,000 you actually thought about. Pick a date and see what would have happened if you bought Bitcoin back then — or a little every month — using real historical prices, not a made-up growth rate.
A historical replay, not a forecast. Results use dated observed prices and assume you held the Bitcoin without selling.
Your Bitcoin time machine
The ride between then and now
The solid line is what the Bitcoin would have been worth at each dated observation. The dashed line is the cash you put in. Nothing is smoothed or interpolated.
Same cash. Different ending.
A different day changes the story
These alternatives hold your amount, valuation date, currency and fee rate constant. They do not replace your result.
All at once, or bit by bit?
Make those Bitcoin numbers feel real
How prices were chosen
Source. Historical BTC/USD observations come from the mempool.space historical price API. Its early series is weekly MtGox data, followed by Kraken observations. The numbers are provider-dated reference observations, not live quotes or actual trade fills.
Date matching. A purchase uses the first observation on or after the requested date, within 7 days in the weekly era and 1 day in the daily era. A valuation uses the last observation on or before the requested date, within the same tolerance. The actual dates are shown above. Missing observations are never interpolated or filled with today’s price.
Other currencies. Non-USD prices are BTC/USD multiplied by the historical USD-to-local reference rate for the same UTC date from Frankfurter. The selector does not merely relabel a USD result.
Fees and limits. The buy fee is deducted from the gross amount. No selling fee, spread, tax, inflation or custody cost is modelled. BTC quantities are calculated without rounding each purchase to a whole satoshi; the satoshi figure is a display conversion of the modelled balance. This is a historical arithmetic exercise, not a forecast or a recommendation.
A missed investment is easy to remember. The whole journey isn't.
Everyone has a Bitcoin story. Someone nearly bought it years ago. Someone sold too early. Someone was sure it had already gone too far.
It's tempting to do the maths with two prices — the one you remember seeing, and the one on the screen today. But that skips the bit in between: the weeks when it looked unstoppable, the months when it dropped, and the question of whether you would really have held on.
This calculator puts the dates back into the story. Choose a one-time purchase or a regular habit and see what the numbers would actually have done, including the down days. You can move your starting date, change the contribution or add trading fees without pretending you can go back and make the perfect decision.
It isn't a crystal ball, and it's definitely not a suggestion to buy Bitcoin now. It's a way to understand the arithmetic behind one of the market's most famous ‘what ifs’.
Bitcoin maths gets weird surprisingly fast
🪙 A tiny slice of a Bitcoin is still a lot of pieces.
Bitcoin divides into 100 million satoshis. Just 0.001 BTC is 100,000 sats. You don't need to buy a whole Bitcoin for the numbers to start looking impressive.
📉 A 50% crash needs a 100% comeback.
If something worth $1,000 falls to $500, it needs to double just to get back to $1,000. A 20% drop needs a 25% rise to recover. Percentages are not symmetrical, however much we wish they were.
🛒 A falling price buys you more Bitcoin for the same money.
Spend $100 when Bitcoin costs $100,000 and you get 0.001 BTC. Spend the same $100 when it costs $50,000 and you get 0.002 BTC. That's twice as much Bitcoin for the same dollars — before fees. Whether it turns out to be a good deal is a different question.
🌙 Friday night is a trading day.
Bitcoin doesn't close for the weekend. Your hypothetical Sunday purchase still has a market-price date, even while traditional currency reference rates might be taking a break.
🎢 You can be up 200% and still feel the next 50% fall.
A $1,000 investment that triples is worth $3,000. A 50% decline from there leaves $1,500. You're still above where you began, but half the peak value has disappeared. That's why a chart tells more of the story than a single return percentage.
How does this Bitcoin calculator work?
This isn't compound interest. Bitcoin doesn't pay a fixed 7% or 10% every year. The calculator uses a historical price for every simulated purchase, works out the Bitcoin bought, and then values those holdings at the historical end price.
Use it as a Bitcoin historical return calculator, a Bitcoin DCA calculator, or a Bitcoin profit or loss calculator. The chart also shows the Bitcoin price history for the dates you choose, including the falls between the endpoints.
One-time investment
For a local-currency investment I, a decimal purchase fee f, a purchase price Pbuy and an end price Pend:
Amount used to buy BTC = I × (1 − f)BTC acquired = [I × (1 − f)] / PbuyEnd value = BTC acquired × PendProfit or loss = End value − ITotal return % = 100 × (End value − I) / I
The fee is deducted from the gross amount. Spending 100 with a 1% fee buys 99 of Bitcoin; the calculator does not quietly assume you spent 101. The fee appears separately in the result.
Regular investing
This is Bitcoin dollar cost averaging in practice (also written dollar-cost averaging): each scheduled purchase is priced on its own observed date, and the portfolio holds the sum of every purchase.
BTC bought in purchase i = [Ii × (1 − f)] / PiTotal BTC = sum of all BTC boughtTotal invested = sum of all gross purchasesEnd value = Total BTC × PendAll-in average cost per BTC = Total invested / Total BTC
Weekly means every 7 calendar days and fortnightly means every 14 days. Monthly purchases keep the original day of the month where possible, use the month’s last day when it is shorter, then return to the original day in later months: 31 January, 28 February, 31 March. The last purchase is included only when its scheduled date is on or before the valuation date.
The simple return for a regular plan is not an annualised money-weighted return or XIRR. The calculator does not divide the total return by the number of years, because that would overstate what a changing contribution schedule means.
For a one-time purchase only, the result panel also shows CAGR: the constant yearly rate that would turn the gross amount into the ending value over the holding period. It annualises that single result and is not shown for a regular plan.
Historical currency conversion
BTC/USD observations are multiplied by the USD-to-local reference rate for the same UTC date. That happens on every purchase date and on the valuation date. A euro result is not a dollar result with a different symbol.
An imagined example, not a dated result
The prices below are made up to explain the formula. They are not historical Bitcoin prices and are never used as a backtest on this page.
Imagine Bitcoin was priced at 20,000 on the purchase date and 30,000 on the valuation date. A 1,000 purchase with a 0.5% fee acquires 0.04975 BTC. The ending value is 1,492.50 — a 492.50 gain, or 49.25% on the 1,000 spent.
What the chart and comparisons do
At each observation, the portfolio value is the Bitcoin held at that point multiplied by the observed local price. The cash line is the gross amount contributed up to that date, including modelled fees. The “same cash” bars compare the nominal cash with the ending Bitcoin value; the Bitcoin bar is allowed to be shorter when the scenario lost money.
The biggest-fall figure is a peak-to-trough drawdown measured between the observed prices in the selected period. In regular-investing mode the calculator also reports the portfolio’s own drawdown, which is not the same thing as the Bitcoin price drawdown. Weekly data can miss falls that happened between observations.
What is deliberately left out
No tax, selling fee, spread, deposit fee, custody fee, inflation or interest is modelled. The result assumes the Bitcoin was held throughout and values it before any sale. It is not a prediction, a recommendation or a promise that any past pattern will repeat.
Bitcoin Investment Calculator FAQs
Is this a Bitcoin price prediction tool?
No. It replays dated historical prices and shows what a past purchase would have been worth at a later historical observation. It does not forecast a future Bitcoin price, suggest that now is a good time to buy, or promise that past returns will repeat.
What prices does it use, and how current are they?
It uses a fixed snapshot of BTC/USD observations from the mempool.space historical price API. The dataset starts in July 2010 and the latest observation is shown on the page. It is not a live quote: the page tells you the latest verified date rather than calling it “today”.
Why is the purchase date sometimes different from the one I picked?
Older price history is weekly. If there is no observation on your exact date, the calculator uses the first observation on or after it within 7 days (or within 1 day in the daily era) and shows the date it actually used. A valuation uses the last observation on or before the date. It never interpolates or borrows a future price from beyond the selected end date.
Does it include exchange fees?
Only the buy fee you enter. It is deducted from the gross purchase amount, so a 1% fee on 100 buys 99 of Bitcoin. Real exchanges may also charge spreads, deposit or withdrawal fees, and those are not modelled. There is no selling fee because the scenario assumes you held throughout.
What about tax when I sell?
Tax is not included. The ending value is a before-tax, before-selling-cost value. Real tax depends on where you live, how long you held, your other income and rules that this calculator cannot know. Treat the result as arithmetic, not a tax calculation.
Why does the result change when I choose another currency?
Because it uses a real historical exchange rate, not just a different symbol. The BTC/USD observation is multiplied by the USD-to-local reference rate for the purchase and valuation dates. Currency movements can make a local-currency result different from the USD result. If a historical rate were unavailable, the calculator would show an unavailable state rather than quietly use today’s rate.
What is dollar-cost averaging, and why compare it with a lump sum?
Dollar-cost averaging means buying a fixed amount on a schedule instead of investing everything at once. The comparison invests the same total gross cash as one lump sum on the first purchase date, with the same fee and end date. It is not a like-for-like cash-flow comparison: the lump sum has all the capital working from day one, while the regular plan spreads it over time. Neither approach always wins.
Would I really have held through the drops?
That is the part no calculator can answer. The chart shows the observed falls, including the drawdown from a previous peak. A real investor might have sold, moved the money, or stopped contributing. The result assumes every planned purchase happened and every satoshi was held to the end.
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