Compound Interest (Periodic)
Also known as compound interest formula
Enter your known values, leave one input blank, and solves for the missing one. Try different units for next level excitement!
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With periodic compounding, each period's rate r is split into n slices and applied n times, so past interest starts earning interest of its own. $5,000 at 4% per year compounded monthly (n = 12) for 10 years grows to A = 5000 × (1 + 0.04/12)¹²⁰ ≈ $7,454.16 — about $50 more than yearly compounding would give, because 120 small boosts beat 10 large ones.
Solving for r recovers the rate a savings product actually paid between two statements, and solving for t answers "how long until my balance reaches A?" Enter r as a decimal (4% → 0.04), and note that pushing n toward infinity lands on the continuous-compounding formula A = Pe^(rt).
- = Final amount
- = Principal
- = Interest rate per period (decimal)
- = Compounds per period
- = Number of periods
- Final amount — Exponential Growth, Exponential Decay
- Principal — Simple Interest, Continuous Compounding
- Interest rate per period (decimal) — Simple Interest, Continuous Compounding
- Compounds per period — Exponential Growth, Exponential Decay
- Number of periods — Exponential Growth, Exponential Decay