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ConvertMyStuff
Tool

Compound Interest Calculator

Project compound interest growth over time.

Finance / Percentage Calculators

What this tool does

Estimate future value and interest earned with compound growth assumptions.

How to use

  1. Enter principal, annual rate, years, and compounding periods per year.
  2. View future value and total interest.

Formula

A = P(1 + r/n)^(nt)

Examples

$10,000 at 5% for 10 years, compounded monthly

Input: P=10000, r=5, t=10, n=12

Output: ≈ $16,470 future value

Monthly compounding grows faster than annual.

Compare quarterly vs annual

Input: P=5000, r=6, t=5, n=4 vs n=1

Output: Quarterly compounding yields a higher ending balance than annual at the same rate.

More compounding periods per year increase effective growth.

Learn more

How compound growth is calculated

Future value uses A = P(1 + r/n)^(nt): principal P, annual rate r, compounding periods per year n, and years t.

More frequent compounding (monthly vs annual) increases ending balance for the same nominal rate.

Assumptions

  • Fixed rate for entire period.
  • No withdrawals or additional deposits.
  • Estimate only—not financial advice.

Common use cases

  • Estimate savings growth
  • Compare compound vs simple interest
  • Plan long-term investment scenarios

FAQ

Is this investment advice?

No. This is an estimate using fixed inputs.

What compounding frequency should I use?

12 for monthly, 4 for quarterly, 1 for annual.

Can I download the schedule?

Yes. Export the year-by-year schedule as CSV from the tool.

Does it account for contributions?

No. Only initial principal compounds in this version.

Source notes

  • Standard compound interest formula A = P(1 + r/n)^(nt).
  • See linked resources for simple vs compound comparisons.

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Last reviewed: 2026-06-02