Percentage Calculator
Solve every kind of percentage problem in one place.
✓ Professional standard Applies standard mathematical formulas and conventions for accurate, verifiable results.
Percentage Calculator is a free online calculator from Toolinza. Solve every kind of percentage problem in one place. It runs entirely in your browser — your data is never uploaded — needs no signup, and works on any device. Toolinza offers 274+ free tools used by people across the UK, USA, Canada, Australia, the EU, India, Pakistan, the Middle East and worldwide.
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About the Percentage Calculator
Percentages are everywhere — discounts, tips, tax, exam scores, interest and statistics all rely on them — yet many people freeze when they have to work one out under pressure. The good news is that every percentage problem follows one of a few simple patterns.
This Percentage Calculator solves them all in one place: finding a percentage of a number, working out what percentage one number is of another, and calculating percentage change. Enter your figures and get the answer instantly, with no risk of a mental-maths slip.
How to use the Percentage Calculator
- Choose the type of percentage problem you want to solve.
- Enter your numbers into the relevant fields.
- The answer is calculated instantly.
- Read the result, ready to use or copy.
Key features of the Percentage Calculator
- Solves every common percentage problem
- Percentage of a number, and reverse
- Percentage increase and decrease
- Instant, accurate results
- Private — calculated in your browser
How the Percentage Calculator works
Each calculator applies the standard mathematical formula for its task — whether that is percentages, areas and volumes, averages, ratios or date arithmetic — following conventional order of operations and calendar rules (including leap years where relevant). Calculations run in your browser and update instantly.
Tips & best practices
- To find a percentage of a number, multiply by the percentage as a decimal — 20% of 80 is 0.20 x 80 = 16.
- For a quick 10%, just move the decimal one place; halve that for 5%.
- Percentages are reversible: 8% of 50 equals 50% of 8, and the second is often easier to do in your head.
Standards & accuracy
Applies standard mathematical formulas and conventions for accurate, verifiable results.
Results follow standard mathematical conventions. For very large or high-precision scientific work, be mindful of normal floating-point rounding, as with any digital calculator.
Who uses the Percentage Calculator?
- Working out discounts and sale prices
- Calculating tips and tax
- Finding exam scores and grades
- Everyday and business percentage maths
Privacy & security
The Percentage Calculator runs entirely inside your web browser. Your data — whether that is a file, figures or text — is processed on your own device and is never uploaded to a server, stored or shared. There is no signup and no account, so you can use it as often as you like while keeping full control of your information. This makes it a safe choice even for confidential and sensitive work.
Why choose Toolinza?
- 100% free — no hidden charges, watermarks or usage caps.
- Private & secure — your data stays on your device.
- Standards-compliant — accurate results suitable for the UK, USA, Canada, Australia, EU, India, Pakistan, the Middle East and worldwide.
- Works everywhere — desktop, tablet and mobile.
Frequently asked questions
Multiply the number by the percentage written as a decimal. For example, 20% of 80 is 0.20 x 80 = 16. The calculator does this instantly.
Subtract the old value from the new, divide by the old value, then multiply by 100. A rise from 50 to 60 is a 20% increase.
Yes. It can find the original amount before a percentage was added or removed, which is handy for backing tax out of a total.
Yes. The Percentage Calculator is completely free with no signup, no watermarks and no usage limits. Toolinza is supported by unobtrusive advertising so every tool stays free.
Absolutely. This tool runs entirely in your browser — your data and files are never uploaded to any server, so everything stays private on your own device.
No. The Percentage Calculator works instantly in any modern web browser on desktop, tablet and mobile — Windows, macOS, Linux, Android and iOS.