Percentage Calculator — How to Use It Online for Free
The Percentage Calculator handles the three percentage questions everyone actually asks: what is X% of Y, X is what percent of Y, and what is the percentage increase or decrease from one value to another. Marks, discounts, growth, interest — all of them are one of these three.
Percentages confuse because the base keeps changing: a 50% loss needs a 100% gain to recover, and '20% off then 10% off' is 28% off in total, not 30%. Having the three standard forms in one place, clearly labelled, removes the guesswork about which formula a question wants. Students, shopkeepers and anyone reading a salary-hike letter all meet the same three shapes.
How to use the Percentage Calculator
- Choose the calculation you need — percent of, percent value, or percentage change.
- Type the two numbers.
- Read the result instantly.
- Use the neighbouring calculation if you need the reverse (for example, the change back).
A worked example
Your salary goes from Rs 38,000 to Rs 41,800. Percentage change = (3,800 ÷ 38,000) × 100 = a 10% hike. Now you know exactly what the letter's '10%' means in rupees.
Tips for better results
- For marks: obtained ÷ total × 100 — the total always goes underneath.
- Percentage points and percent are different: 10% → 12% is +2 points, but a 20% relative rise.
- For discounts on top of discounts, apply them one at a time with the Discount Calculator.
A note on online calculators
Online calculators are only as good as the numbers typed into them, so two habits matter. First, decide what the result should roughly be before you calculate — an expected range catches the classic errors, like a misplaced decimal or a rate entered per month instead of per year. Second, read the labels: many money mistakes are really direction mistakes (adding tax instead of removing it, dividing by the new value instead of the original). The calculators here show the full picture — not just the headline figure but the totals and splits behind it — so you can see whether the answer makes sense, and adjust the inputs until it does.
Common questions
How do I find what percent my marks are? Use 'X is what percent of Y': X = marks obtained, Y = total marks. 342 out of 500 gives 68.4%. The same pattern works for attendance, savings targets and discounts taken.
A price rose from 800 to 1,000. What is the increase? Percentage change: (1000 − 800) ÷ 800 × 100 = 25% increase. Always divide by the ORIGINAL value — dividing by the new value is the classic mistake.
Do I need to sign up or install anything? No. The Percentage Calculator is completely free, needs no account and nothing to install — it runs in your browser, and anything you type stays on your device.
One tool rarely finishes the whole job. The natural companions to this one are covered in the Age Calculator guide and the Unit Converter guide — between them, most calculation tasks can be handled end to end in the browser, with no installs and no accounts.