Interest Calculator

Estimate simple or compound interest on a lump-sum balance.

Inputs

Result

Future value
$16,470.09
Interest earned: $6,470.09

Visual breakdown

Principal $10,000.00 — 61%
Interest earned $6,470.09 — 39%

Formula

Simple: A = P(1 + rt). Compound: A = P(1 + r/n)^(nt). All rates as decimals; t in years.

Example

$10,000 at 5% for 10y, monthly compounding ≈ $16,470.

Related: Savings · Loan payment · Mortgage

Common examples

$10,000 @ 5%, 10y
Compounded annually ≈ $16,289.
Simple 4% on $5,000, 3y
= $600 interest.
$1,000 monthly contribution
Compounded growth over years.

Frequently asked

Simple vs compound?

Simple interest accrues only on the principal. Compound interest also earns interest on prior interest.

What does APY vs APR mean here?

We use a nominal annual rate compounded n times per year. APY is what you actually earn after compounding.

Are taxes included?

No — this is a pre-tax estimate. Your real return will depend on local taxes.

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More money & work

Estimates only — not financial advice. Real returns vary with fees, taxes and rate changes.