Finance
Simple Interest Calculator (P × R × T)
Calculate simple interest, total amount, and daily interest for any loan.
In this article
The simple interest formula
I = P × R × T
I = Interest P = Principal R = Rate (decimal) T = Time (years)
Simple vs compound interest
Simple interest only applies to the original principal. Compound interest applies to principal plus previously earned interest. For savings, compound is always better. For loans, simple is cheaper — though most loans compound monthly.
Frequently asked questions
What is the simple interest formula?▾
I = P × R × T. On $10,000 at 5% for 3 years: $10,000 × 0.05 × 3 = $1,500 in interest.
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