Simple Interest Calculator
Find simple interest and total amount for any principal, rate and time.
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Detailed breakdown
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What is the Simple Interest Calculator?
Simple interest is interest calculated only on the original principal. It does not compound, so the interest earned each year stays the same. It is used in many short-term loans, notes and basic maths problems.
How to use this calculator
- Enter your values in the input fields. Use the sliders where available for quick changes.
- Choose the options that fit your case - currency, number format and decimals can be changed in the Options bar.
- The result updates instantly as you type. Press Calculate to refresh.
- Review the summary, the chart and the detailed table (when shown).
- Use Export & share to download a snapshot image (PNG or JPG), copy the result, print, save a CSV, or copy a link that reopens your inputs.
Formula and method
Amount = P + SI
P = principal, R = rate % per year, T = time in years.
Worked example
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Options you get
- Currency symbol and Indian or international digit grouping
- Decimal places control
- Instant results with charts and tables (where relevant)
- Snapshot image export (PNG / JPG), copy image, CSV, print and share link
- Light and dark themes - works on mobile, tablet and desktop
Frequently asked questions
What is the difference between simple and compound interest?
Simple interest is earned on the principal only; compound interest is earned on principal plus previously earned interest.
How do I convert months to years?
Divide months by 12. This calculator does it automatically when you choose Months.
Is this calculator free to use?
Yes. All MCSBiz calculators are free, work in your browser and need no sign-up.
Is my data stored or sent to a server?
No. Calculations run on your own device. Your inputs are not uploaded, and nothing is saved unless you choose to share a link or export an image.
Can I save or share my result?
Yes. Use "Download PNG" or "Download JPG" to export a snapshot image, copy the result, print it, download a CSV, or copy a link that reopens the calculator with your inputs.
Important note
Results are estimates based on the inputs and assumptions shown. Investments are subject to market risk and past performance does not guarantee future returns. This is not financial, tax or legal advice - please verify with official sources or a qualified professional.