finance • calculator • Statutory 2026 Engine

Simple Interest Calculator (I = P × r × t)

Calculate simple interest, total balance, and daily accrual rates instantly with the standard I = P × r × t formula on UtilityBase.

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Worked Example: $10,000 at 6.5% Annual Simple Interest for 3 Years

A private lender issues a $10,000 personal promissory note at 6.5% flat simple interest over 3 years.

Original Principal$10,000.00
Annual Interest Accrual ($10K × 0.065)$650.00/year
Total Simple Interest (3 Years)$1,950.00
Total Amount to Repay at Maturity$11,950.00

Total simple interest is $1,950.00, resulting in a total final repayment of $11,950.00.

Frequently Asked Questions

What is the main difference between simple and compound interest?

Simple interest is computed strictly on the original principal. Compound interest is calculated on the principal plus any accumulated interest from prior periods, causing balances to grow exponentially rather than linearly.

Where is simple interest used in real life?

Simple interest is commonly used for short-term personal loans, automobile loans, pawn shop transactions, and certificate of deposit (CD) accounts that pay interest out directly to checking accounts rather than compounding.