% Percentage Calc
Calculate percentages free: percentage of a number, percentage change, increase and decrease. Instant, accurate results.
% Percentage Calc
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About the Percentage Calc Tool
Percentages come up constantly — discounts, tips, interest, exam marks, price changes — and the arithmetic is simple enough that people attempt it mentally and get it wrong regularly. The most common error is percentage change, where the choice of base matters and reversing a change does not return you to the start.
A 50% increase followed by a 50% decrease leaves you at 75% of the original, not back where you started. This calculator handles the standard percentage operations correctly, instantly, in your browser.
How to Use Percentage Calc
- Choose the type of percentage calculation you need.
- Enter your values.
- The result is calculated immediately.
- Read the answer along with the working where shown.
When to Use This Tool
- Calculating a discount and the final sale price
- Working out percentage change between two figures
- Computing a tip or service charge
- Converting exam marks into a percentage score
- Calculating profit margin or markup on a product
Things Worth Knowing
- Percentage change is calculated relative to the original value, not the new one.
- Successive percentage changes compound and do not simply add.
- Margin and markup are different: margin is profit over selling price, markup is profit over cost.
Quick Facts
| Tool name | Percentage Calc |
| Category | Utilities |
| Price | Free — no account, no trial, no watermark |
| Where it runs | Entirely in your browser (client-side) |
| Files uploaded | None — your data never leaves your device |
| File size limit | None imposed; limited only by device memory |
| Works offline | Yes, once the page has loaded |
| Platforms | Windows, macOS, Linux, Android, iOS |
Frequently Asked Questions
How do I calculate percentage change?
Subtract the old value from the new, divide by the old value, and multiply by 100. From 80 to 100 is (100 − 80) ÷ 80 × 100 = 25% increase. Dividing by the new value instead is the classic mistake.
Why does a 50% rise then a 50% fall not return to the start?
Because the second percentage applies to a larger base. 100 rises to 150, and 50% of 150 is 75, leaving you at 75. Percentage changes compound multiplicatively, not additively.
What is the difference between margin and markup?
Markup is profit as a percentage of cost; margin is profit as a percentage of selling price. An item costing ₹100 sold at ₹150 has 50% markup but 33.3% margin.
How do I find the original price before a discount?
Divide the discounted price by (1 minus the discount as a decimal). An item at ₹800 after 20% off was originally ₹800 ÷ 0.8 = ₹1000.