finance calculator
Model compound growth with deposits and time.
Save this page to compare timelines, contribution amounts, and return assumptions quickly.
Future value
$67,358
Formula
Future value = starting balance compounded monthly + each monthly contribution compounded over timeThe calculator compounds the starting balance and adds each contribution month by month.
Step by step
Example
Starting with $10,000 and adding $300 monthly for 10 years at 6% grows to about $64,198.
Related guides
Guide
Learn how compound interest works, the formula behind exponential growth, and how starting early, regular contributions, and reinvesting dividends accelerate wealth building.
Guide
Compare simple and compound interest calculations. Understand how compounding frequency affects growth and when each interest model applies to loans and investments.
Summary
Future value
$67,358
Projected ending balance.
Contributions
$46,000
Starting amount plus monthly contributions.
Interest earned
$21,358
Estimated compound growth.
Months invested
120 months
10 year horizon.
D3 visualization
Separate money contributed from compound interest earned.
D3 visualization
A sampled monthly projection shows how compounding builds over time.
Guide
The compound interest calculator estimates future value from an initial amount, monthly contribution, annual return, and number of years. It shows how much comes from contributions and how much comes from compound growth.
It is useful for savings, investing, education funds, and long-term planning where the timing of deposits affects the final result.
Enter the starting amount, monthly contribution, annual return, and years. Review the ending value, total contributions, and interest earned.
Use the timeline chart to see how growth accelerates over longer periods. Compounding usually becomes more visible later in the timeline.
Each month, the calculator multiplies the balance by one plus the monthly rate, then adds the monthly contribution. Repeating that process creates compounding.
If the return rate is zero, future value is simply the starting amount plus all contributions.
Principal
The starting amount before growth and contributions.
Monthly compounding
Growth applied once per month.
Future value
The estimated ending balance after compounding.
Compound interest means interest is earned on both the original money and prior interest.
Longer timelines give each dollar more periods to compound.
It can model either, as long as the return assumption matches the product or portfolio being tested.