Simple Interest Calculator
Calculate simple interest (I = P x r x t) with principal, rate, and time. View month-by-month breakdown and export CSV. Free, fast, and works entirely in your browser with no sign-up required.
Simple Interest Calculator
Calculate simple interest (I = P x r x t) with total amount, monthly breakdown, CSV export, and copy-to-clipboard support.
Loan / Investment Details
Principal
Interest Earned
Total Amount
Calculation Summary
- Principal (P)
- $10,000.00
- Annual Rate (r)
- 5.00%
- Time (t)
- 3.0000 years (36 months)
- Interest per month
- $41.67
- Interest per day
- $1.37
- Total interest
- $1,500.00
- Total Amount (A)
- $11,500.00
Frequently Asked Questions
What is simple interest?
Simple interest is interest earned only on the original principal using I = P x r x t, never on previously accumulated interest.
How is it different from compound interest?
Simple interest stays flat each period; compound interest earns interest on prior interest, so it grows faster over time.
Can I enter time in months?
Yes. Toggle between Years and Months — the calculator converts months to years internally (months / 12).
Is the Simple Interest Calculator free to use?
Yes, the Simple Interest Calculator is 100% free with no registration, no hidden fees, and no usage limits. All processing happens locally in your browser, ensuring complete privacy.
Is my data safe with this tool?
Absolutely. The Simple Interest Calculator processes everything client-side in your browser. No data is uploaded to or stored on any server. Your content remains private on your device at all times.
Does the Simple Interest Calculator work on mobile devices?
Yes, the Simple Interest Calculator is fully responsive and works on smartphones and tablets. You can use it on any device with a modern web browser -- no app download required.
Do I need to create an account to use this tool?
No account or registration is needed. Simply open the Simple Interest Calculator in your browser and start using it immediately. There are no sign-up walls or usage restrictions.
How accurate are the calculations?
The Simple Interest Calculator uses industry-standard formulas and algorithms to ensure accurate results. However, for critical financial or medical decisions, always consult a qualified professional.
How do I use the Simple Interest Calculator?
Simply enter your input in the provided field, adjust any settings to your preference, and the tool will process it instantly. You can then copy the result to your clipboard or download it.
Which browsers are supported?
The Simple Interest Calculator works in all modern browsers including Chrome, Firefox, Safari, Edge, and Opera. For the best experience, use the latest version of your preferred browser.
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About Simple Interest Calculator
Simple Interest Calculator is a free, browser-based tool in our Calculator Tools collection. Everything runs locally on your device — no uploads, no sign-up, and your data stays private.