No uploads · runs in browser
Compound Interest Simulator
See how a lump sum grows with compound interest, year by year, with optional monthly contributions.
Favorite it to find it fast on home
When to use it
$300 a month at 5% for 10 years
$10,000 lump sum at 5% for 10 years
See how interest overtakes contributions over 20 years
How to use it
1Step 1Fill in Starting amount
2Step 2Change a value and the result updates instantly
3Step 3Save or copy the result
If the result looks off
The result looks wrong
Check the units and the baseline first. Changing a value updates the result instantly.
I want the starting values back
Press reset to return to the initial state.
Frequently asked questions
Can I include monthly contributions?
Yes — enter a monthly amount and it compounds alongside your starting balance.
Do I see a yearly breakdown?
Yes. A table shows the balance and interest earned for each year.
Is the interest compounded monthly?
It compounds monthly, which matches how most savings accounts and funds report growth.