Finance 9 min read

Simple vs Compound Interest: Formulas, Differences & Growth Comparison

Compare simple interest and compound interest formulas. Learn how compounding frequency affects long-term investment growth and loan interest.

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Simple Interest vs Compound Interest

Simple interest is calculated exclusively on the original principal amount. Compound interest calculates interest on the principal PLUS all previously accumulated interest ("interest on interest").

The Growth Comparison Formulas

  • Simple Interest: I = P × r × t | Total = P(1 + rt)
  • Compound Interest: A = P(1 + r/n)ⁿᵗ

10-Year Growth Example ($10,000 at 8%)

  • Simple Interest: $10,000 + (10,000 × 0.08 × 10) = $18,000
  • Compound Interest (Annual): $10,000 × (1.08)¹⁰ = $21,589.25
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Reviewed by Applied Math Specialists • Editorial Policy
Updated: August 11, 2026

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