Simple Interest Calculator 2026
Fast & accurate simple interest calculator. Calculate SI on loans, savings & investments. Find principal, rate, time or total amount instantly.
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Frequently Asked Questions
Clear answers to common questions to help you use this calculator confidently.
What is simple interest?
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What is simple interest?
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Simple interest is interest calculated only on the principal amount, not on accumulated interest. Formula: SI = (Principal × Rate × Time) ÷ 100.
How is simple interest different from compound interest?
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How is simple interest different from compound interest?
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Simple interest is calculated only on principal. Compound interest is calculated on principal plus previously earned interest ("interest on interest"), resulting in faster growth.
What is the simple interest formula?
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What is the simple interest formula?
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SI = (P × R × T) ÷ 100, where P = Principal, R = Annual Interest Rate (%), T = Time in years. Total Amount = Principal + Simple Interest.
How do I calculate simple interest for months or days?
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How do I calculate simple interest for months or days?
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Convert to years first. For months: divide by 12. For example, 6 months = 0.5 years. For days: divide by 365. Then use the standard formula.
Is simple interest or compound interest better for savings?
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Is simple interest or compound interest better for savings?
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Compound interest is better for savings and investments because it grows faster. Simple interest is fine for short-term loans where you pay all at once at the end.
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