Compound Profit Calculator
See what reinvested profits grow into. Enter the starting amount, annual return rate, compounding frequency, and years, plus an optional monthly contribution. The calculator returns the future value, the total profit earned, and how much came from your contributions versus compounding.
Worked example, checked against this exact tool
$10,000 at 10% compounded monthly for 5 years with $100/month contributions: the starting amount grows to $16,453.09, the contributions grow to $7,743.71, for a future value of $24,196.80. You put in $16,000 total; compounding earned you $8,196.80 in profit.
The formulas
Future value of principal: A = P(1 + r/n)nt, with P the starting amount, r the annual rate, n the compounding periods per year, and t the years. Future value of monthly contributions: PMT × (((1 + i)N − 1) ÷ i), with i the monthly rate and N the number of months. Profit = future value − starting amount − total contributions.
Why contributions beat rate-chasing
A higher rate helps, but regular contributions dominate most real outcomes: in the example above, the $6,000 of contributions earned nearly half the total profit through compounding. Time matters more than timing: starting 5 years earlier at a lower rate usually beats starting later at a higher one.
What competing calculators miss
The rival with contribution support is the feature bar and this page matches it, while the thin calculators ignore contributions entirely. This page adds the profit-vs-contributions breakdown so you can see exactly what compounding earned versus what you put in.
Frequently asked questions
How do you calculate compound profit?
A = P(1 + r/n)^nt for the starting amount, plus the future-value-of-annuity formula for regular contributions.
What is the difference between compound profit and compound interest?
The same math. “Profit” here just means reinvested business or investment returns instead of bank interest.
How often should profits compound?
More frequent compounding grows slightly faster. Monthly vs annual at 10% over 5 years differs by about $94 on $10,000.
Do contributions really matter that much?
Yes. In the worked example, $6,000 of contributions generated nearly half the $8,197 profit through compounding.
What is a realistic annual return?
Stock markets have averaged about 10% nominal (7% real) long-term; business reinvestment varies widely. Use conservative rates for planning.
Does this include taxes?
No. Enter an after-tax rate or subtract expected taxes from the result.
What if the rate is 0%?
The future value is just the starting amount plus contributions: no growth.
Can the rate be negative?
The tool accepts it and shows the loss, useful for stress-testing losing years.
Monthly vs yearly contributions?
Monthly contributions compound slightly more since money enters earlier. Divide an annual figure by 12 for the monthly input.
How long to double my money?
The Rule of 72: years ≈ 72 ÷ rate. At 10%, about 7.2 years.