Compound Interest Calculator
See how savings grow with compound interest, regular deposits and any compounding frequency — with an inflation-adjusted value and a year-by-year table.
- →Time matters more than rate: starting 5 years earlier often beats a slightly higher return.
- →Compare savings products on the effective annual rate (APY/AER), not the nominal rate.
- →Use a conservative rate for stock or fund investments — returns are not guaranteed.
- →Add an inflation rate to see what your future balance can actually buy.
This tool is for informational purposes only. Always verify results with a qualified professional.
What is the Compound Interest Calculator?
The Compound Interest Calculator shows how an initial lump sum and regular deposits grow over time when the interest you earn also starts earning interest. Enter a starting amount, an optional monthly or yearly contribution, the annual rate, how often interest is compounded and the number of years. You get the final balance, how much of it you paid in yourself, how much is interest, and what that balance is worth in today's money after inflation. A year-by-year table shows exactly when the growth curve starts to bend upward.
For a single deposit the formula is A = P(1 + r/n)^(nt), where P is the starting amount, r is the annual rate as a decimal, n is the number of compounding periods per year and t is the number of years. Regular contributions add an annuity part: PMT × ((1 + i)^(m) − 1) ÷ i, where i is the growth rate per contribution period and m is the total number of contributions. If you contribute at the start of each period instead of the end, every deposit gets one extra period of growth, so that part is multiplied by (1 + i). When the contribution and compounding frequencies differ, the calculator converts the rate to the matching per-period rate so the result stays exact.
Worked example: you invest USD 10,000 and add USD 200 at the end of every month for 20 years at 8% a year, compounded monthly. The lump sum alone grows to about USD 49,268, and the monthly deposits grow to about USD 117,804, for a final balance of roughly USD 167,072. You paid in USD 58,000 in total, so about USD 109,072 — almost two-thirds of the balance — is compound interest. With 3% yearly inflation, that balance would buy what about USD 92,504 buys today.
Two quick rules help you sanity-check any savings plan. The Rule of 72 says money doubles in roughly 72 ÷ rate years, so at 8% a sum doubles in about 9 years. The effective annual rate (EAR) = (1 + r/n)^n − 1 shows the true yearly growth after compounding: 8% compounded monthly is an EAR of about 8.30%, while 10% compounded daily is about 10.52%. When comparing savings accounts or certificates, compare EARs (often shown as APY or AER), not the headline nominal rate.
Islamic savings products such as Mudarabah-based deposits, Islamic certificates and Shariah-compliant funds do not pay a fixed interest rate. They share actual profit, so returns vary with the bank's or fund's performance and are announced as a profit rate after each period. You can still use this calculator to model them by entering an expected profit rate, but treat the result as an illustration rather than a guaranteed figure. The same applies to stock and mutual fund returns, which go up and down from year to year.
How to Use This Calculator
- 1Pick your currency: USD, PKR, AED, SAR, GBP, EUR or INR.
- 2Enter the initial amount you are starting with (it can be zero).
- 3Add a regular contribution, choose monthly or yearly, and choose whether you deposit at the start or end of each period.
- 4Enter the annual interest or expected return rate and the compounding frequency.
- 5Enter the number of years and, optionally, an inflation rate to see the real value.
- 6Click Calculate, then open the year-by-year table to see contributions, interest and balance for every year.