Compound Interest & Savings Goal
See how your savings grow with monthly contributions and compound interest.
Enter your savings details to see how your money grows over time.
Formula
How to calculate
- 1Divide the annual rate by the compounding frequency (r/n).
- 2Multiply the frequency by the years (n·t).
- 3Raise (1 + r/n) to that power and multiply by the principal.
- 4Subtract the principal from the result to isolate the interest earned.
How to use this calculator
- 1Enter your starting amount and monthly contribution.
- 2Set the annual return rate and the number of years.
- 3Choose how often interest compounds.
- 4Watch the projected balance and a growth chart update instantly.
Examples
Monthly saving
$200/month at 7% for 30 years → ≈ $244,000 from $72,000 of contributions.
One-time deposit
$10,000 at 5% compounded monthly for 20 years → ≈ $27,126, with the growth accelerating in the later years.
Common questions
Why does compounding frequency matter?
More frequent compounding earns interest on interest sooner, so monthly beats annual at the same nominal rate — compare APYs to see the true difference.
What rate should I assume?
Long-run stock market returns are often modeled at 6–8% before inflation; savings accounts are lower. Test a few rates to see the range of outcomes.
Does inflation affect this?
The nominal projection ignores inflation — subtract roughly 2–3% from the rate for a feel for real purchasing power.
