Interest on the original amount only — nothing compounds.
Total amount
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Principal
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Interest earned
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Total amount
Principal vs interest
Year-by-year table
Year
Interest to date
Total
A plain simple-interest calculation on the figures you enter, not a loan or deposit quote. Real products may compound, add fees, or use a different day-count convention — check the actual terms.
How this works
Interest = Principal × Rate ÷ 100 × Time (years)
Total = Principal + Interest
$10,000 at 6%
Interest
Total
1 year
$600
$10,600
3 years
$1,800
$11,800
10 years
$6,000
$16,000
Interest grows by the same amount every period — a straight line, not a curve. Doubling the time exactly doubles the interest.
Months convert to years as months ÷ 12; days convert as days ÷ 365 (the common banking convention — some products use 360).
Simple interest is common for short-term loans, certain bonds and some school and exam problems. Savings accounts and most loans actually compound — see the compound interest calculator for those.
Currency
Amounts follow the currency selected above.
What is the simple interest formula?
Interest = Principal × Rate ÷ 100 × Time, where time is in years. A $10,000 principal at 6% for 3 years earns $10,000 × 0.06 × 3 = $1,800.
What is the difference between simple and compound interest?
Simple interest is always calculated on the original principal, so it grows by the same amount each period. Compound interest is calculated on the principal plus interest already earned, so it accelerates. Over long periods the difference becomes large — see the compound interest calculator to compare.
How do I calculate simple interest for months or days instead of years?
Convert the time to years first: divide months by 12, or days by 365. Six months is 0.5 years; 90 days is about 0.247 years. This calculator does the conversion for you when you pick Months or Days.