Simple Interest Calculator
Calculate returns on fixed-income investments where interest is applied only to the original principal. Unlike compound interest, there is no reinvestment — returns grow linearly.
Parameters
Final amount
$15,000.00
Principal
$10,000.00
Total interest
$5,000.00
Balance over time
Period breakdown
| Period | Balance | Interest earned |
|---|---|---|
| Start | $10,000.00 | $0.00 |
| Year 1 | $11,000.00 | $1,000.00 |
| Year 2 | $12,000.00 | $2,000.00 |
| Year 3 | $13,000.00 | $3,000.00 |
| Year 4 | $14,000.00 | $4,000.00 |
| Year 5 | $15,000.00 | $5,000.00 |
What is simple interest?
Simple interest is calculated only on the original principal — it does not accumulate. If you invest $10,000 at 10% per year for 5 years, you earn $1,000 every year for a total of $5,000 in interest and $15,000 final value.
Formula used
Interest = Principal × Rate × TimeandFinal = Principal + Interest. Annual rates are divided by 12 when calculating monthly periods. Unlike compound interest, the base never grows — returns are linear.
For educational purposes only. Not financial advice.