Compound Interest Calculator

How to use

How to use Compound Interest Calculator

01
Enter your starting amount
Add your initial principal, or 0 if starting from scratch.
02
Set the rate and term
Enter the expected annual return and number of years.
03
Add contributions
Include a monthly deposit and choose a compounding frequency.
04
Read the projection
See future value, total interest and the yearly growth table.

Use cases

Common use cases

—Project retirement savings growth
—Plan a house-deposit savings timeline
—Compare investing monthly vs a lump sum
—See the effect of compounding frequency

Overview

The power of compounding

Compound interest means you earn interest on your interest, so balances snowball over time. This calculator combines a starting amount, a regular monthly contribution and your expected annual return, then compounds it at the frequency you choose to project the future value. The earlier you start and the more often interest compounds, the larger the final balance — the yearly table makes that growth curve easy to see.

Model any savings goal

Use it to plan a retirement fund, a house deposit, an emergency fund or a child's education. Adjust the rate to run best-case and worst-case scenarios, change the contribution to see how much extra saving speeds you toward your goal, and compare compounding frequencies. Everything is calculated in your browser — no data is uploaded.

Features

01: Interactive year-by-year growth chart
02: Future value, contributions & interest split
03: Monthly or yearly contributions
04: Annual, quarterly, monthly or daily compounding
05: Inflation-adjusted (real) value + 7 currencies
06: Effective annual yield & copy-results

FAQ

Frequently asked questions

How is compound interest calculated?+

Interest is added to your balance each period, then future interest is earned on that larger balance. This tool derives an effective monthly rate from your annual rate and compounding frequency, applies it each month, and adds your contribution.

Does it include monthly contributions?+

Yes. Enter a monthly deposit and it's added every month before the next round of interest, so you see the combined effect of saving and compounding.

What compounding frequency should I choose?+

Match it to your account — savings often compound daily or monthly, while some bonds compound annually. More frequent compounding yields slightly more over time.

Is my data saved?+

No. Every calculation runs in your browser and nothing is uploaded or stored.