Privacy controls
FinanceFormula-based · Runs in your browser

Compound Interest Calculator

Project investment growth with regular monthly contributions and selectable compounding.

Scan this calculator
Preparing saved example…

Inputs

Enter the values you know. Optional fields may be left empty.

Local save controls below
Required
$
Optional
$
Required
%
Required
Required

Result

Updates as valid inputs change.

Calculated locally
Future value
—
Total contributions
—
Growth earned
—
Growth on contributions
—

Saved locally, explained clearly

Drafts, calculations, scenarios, and workflow progress stay in this browser unless you export them.

Opening local database…

Calculation steps

Follow what happened from the selected formula to the displayed answer.

Show substituted values and intermediate working
Calculate current inputs to see the working.
  1. 1

    Formula selected

    The calculator uses the following formula or method.

    FV = P(1 + r/m)ᵐᵗ + PMT × [((1 + i)ⁿ − 1) ÷ i]

    Monthly contributions are added at the end of each month.

  2. 2

    Values entered

    Your values are placed into the calculation.

    Enter values to see what is used in this step.

  3. 3

    Result calculated

    The formula or method produces the following result values.

    Results will appear after a successful calculation.

  4. 4

    Answer formatted

    Displayed values are rounded and formatted using each output’s configured precision.

Scenario comparison

Save working scenarios, then select two or three to compare. Formula versions and inputs remain visible.

No scenarios saved for this calculator yet.

Recent calculations

Successful calculations are retained locally according to your privacy settings.

No local history for this calculator yet.

Data and privacy

How it works

Contributions are added at the end of each month. The selected compounding frequency is converted to an equivalent monthly rate.

Input query strings and outputs

Use an input name in this page’s URL as ?name=value, and join additional inputs with &. Portable shared links may instead use the compact ?ac= state parameter.

Input query strings

5
  • ?initial= Initial investment

    Money · Required · Default: 10,000

  • ?monthly= Monthly contribution

    Money · Optional · Default: 500

  • ?annualRate= Annual return

    Percentage · Required · Default: 7

  • ?years= Years

    Number · Required · Default: 20

  • ?frequency= Compounding

    Choice · Required · Default: 12 · Accepted values: 12, 4, 1, 365

Outputs

4
  • futureValue Future value

    Currency · Primary output

  • contributions Total contributions

    Currency

  • interestEarned Growth earned

    Currency

  • growthPercent Growth on contributions

    Percentage

Reading the chart

The contributions line is money added by you. The balance line includes both contributions and calculated growth.

Limits

The result assumes a fixed rate. It does not include taxes, fees, inflation, or market changes.

Sources
Limitations
  • Monthly contributions are added at the end of each month.
  • Estimates use the rates, timing, and assumptions entered. Fees, taxes, lender rules, and future changes are included only where explicitly shown.

Related calculators

Finance

Savings Calculator

Estimate savings growth and check an optional savings goal.

Open calculator
Finance

ROI Calculator

Calculate profit, total return, return multiple, and optional annualized return.

Open calculator
Finance

Mortgage Calculator

Estimate principal, interest, taxes, insurance, optional HOA fees, and extra payments.

Open calculator