Compound Interest Calculator Excel Formula
Get the same compound interest result and the Excel FV formula to check it yourself.
Runs locally in your browser — your numbers never leave this pageTry: Starting principal=1000, Annual interest rate=5, Compounding=12, Years=20, Monthly contribution=0, Annual inflation=0 → $2,712.64, $1,000.00, $1,712.64
How to use
Compound interest is interest earned on prior interest. Enter your starting principal, the annual rate, and how often it compounds (daily, monthly, and so on). Add a monthly contribution to model regular saving. The calculator reports the final balance, total interest, and — if you enter inflation — the real purchasing power of that balance.
Excel formula: for a lump sum use =FV(rate/nper, nper*years, 0, -principal); for a monthly contribution use =FV(rate/12, 12*years, -monthly, -principal), where rate is the decimal rate (e.g. 0.05).
FAQ
What does compounding frequency change?
More frequent compounding (daily beats annual) gives a slightly higher balance because interest starts earning interest sooner. The difference is small at low rates but grows over long periods.
Why add a monthly contribution?
Regular saving is usually the biggest driver of long-term growth. The calculator treats it as an ordinary annuity added each month.
What is the inflation-adjusted value?
It divides the final balance by (1 + inflation)^years to show what that money could actually buy then, stripping out price rises.