Compound calculator guide
What should you check when reading compound results?
ReturnLab is not just a single-result compound calculator. It compares how nearby daily returns, target amounts, and longer durations change the final result under the same starting conditions.
Compare rates
Compare nearby daily returns such as 1.00%, 1.10%, and 1.20% to see how small differences compound over time.
Work backward
Check how many days a target amount may require, or what daily return would be needed to reach a target within a fixed period.
Compare durations
Compare 20, 40, 60 days and beyond to see why a longer period does not scale in a straight line.
How is the compound result calculated?
Compounding adds each day of gain back into the next day base amount. If 1,000,000 earns 1% on day one, the next day starts from 1,010,000, not from the original amount alone.
The basic formula is final amount = starting amount x (1 + daily return)^days. The longer the period, the more previous gains become part of the next calculation.
Why compare several daily returns at once?
A difference between 1.0% and 1.1% can look small in a single-day view. Side-by-side scenarios make it easier to see how that difference affects final value, target duration, and required return.
This comparison is not a promise of future performance. It is a way to test whether a target depends on a realistic daily return or on an aggressive assumption.
What should you be careful about?
The calculator assumes the same return repeats every day. Real investing includes losing days, fees, taxes, slippage, exchange rates, and execution risk.
When the period is long and the daily return is high, the result can become extremely large. Large values, detail panels, and CSV exports should be treated as approximations within calculable precision.