Lump Sum Compound Calculator
Grow a one-time lump sum with compounded interest and no further deposits.
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.
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.