Simple Interest Calculator
Enter valid positive values for the known fields.
End balance $0.00
Total interest $0.00
| Year | Interest | Balance |
|---|
Free simple interest calculator (non-compounding: I = P × r × t) that solves for any of the four variables — end balance, principal, rate, or time — plus a downloadable year-by-year schedule.
This tool is for informational purposes only and is not a substitute for professional financial or medical advice.
Consult a qualified professional before making decisions. See our Disclaimer.
How it works
- Pick what you want to solve for: end balance, principal, rate, or time
- Fill in the other three known values
- See the result instantly, with a yearly schedule you can download as CSV
Frequently asked questions
What's the difference between simple and compound interest?
Simple interest is calculated only on the original principal every period (I = P × r × t) — it doesn't earn interest on previously accumulated interest. For that, use our Compound Interest Calculator instead.
Can I solve for the interest rate or time instead of the balance?
Yes — switch modes above. Enter the end balance along with two of the other three values, and the tool solves for whichever one you left as the unknown.
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Update history
- 2026-09-01 Added: a cover image (a ruler-like bar with evenly spaced tick marks growing in a straight diagonal line, beside a stack of coins) — used as the card thumbnail, social share image, and blog title image.
- 2026-09-01 Launched: simple interest calculator (no button) — solves for end balance, principal, rate, or time, with a downloadable yearly schedule. Entirely client-side.