Percentage Calculator
Free percentage calculator — what is X% of Y, X is what percent of Y, percentage increase and decrease, discounts, GST, marks, profit margin. Every answer shows its formula.
Percentage Calculator — Calculate All Types of Percentages Instantly
Percentages come up in nearly every calculation — school marks, exam scores, salary hikes, GST, discounts, profit margins, percentage change. This calculator answers fourteen different percentage questions, each written out as a plain sentence you simply fill in.
There is no mode to choose and no button to press. Every question sits on the one page, the answer appears as you type, and underneath it you get the formula with your own numbers substituted in — so you can check the working, or copy it into your homework. Great for students, accountants, shopkeepers, and anyone who deals with numbers daily. No signup, no cost.
Built to be right, not just fast
- No floating-point litter. 1.1 plus 10% gives
1.21, not 1.2100000000000002. Every formula multiplies by 100 before dividing, which we checked against exact fraction arithmetic — ₹575 inclusive of 15% tax comes back as exactly ₹500. - Undefined stays undefined. A percentage change starting from 0 is infinite, and nothing can be a percentage of zero. Those say so plainly instead of showing Infinity or NaN.
- Negatives handled properly. Going from −50 to −25 is reported as a 50% increase, because the value rose. Calculators that divide by the signed starting number call this a decrease.
- Margin and markup are not confused. Buy at 400, sell at 500: that is a 20% margin but a 25% markup. You get both.
How to Use the Percentage Calculator
1. Find Your Question
Every question is written out in plain English — “What is __% of __?”, “__ is what percent of __?”, “percentage change from __ to __”. Nothing to select.
2. Fill In the Blanks
Type the two numbers. You can paste a figure straight from a bill or spreadsheet — 1,20,000 and ₹1,234.50 are both understood.
3. Read the Answer
It appears as you type, with the formula underneath and any extra worth knowing — what you saved, how much tax was inside the price, whether it went up or down.
4. Copy Result
Copy the answer with one click for use in spreadsheets, documents, or messages. Choose your currency and how many decimals you want first.
Percentage Calculator Features
All Percentage Types
“What is X% of Y”, “X is what % of Y”, “X is Y% of what”, percentage increase, decrease, change and difference — plus adding or taking off a percentage.
Marks Percentage
Exam percentage from marks obtained out of total. Scored above the total for bonus marks? It still works, and points out that you did.
Salary Hike
Percentage hike from old to new salary, or apply a hike % to find the new salary — and it tells you the rupee difference too.
Discount Math
Price after discount, the amount you save, and the original price worked backwards from what you actually paid.
GST and Tax, Both Ways
Add tax to a net amount, or strip it back out of a tax-inclusive price to see the base and the tax separately — the reverse GST every shopkeeper needs.
Margin, Markup and Error
Profit margin and markup side by side (they are different numbers, and mixing them up costs money), plus percentage error for lab work.
Formula Display
Every result shows the formula with your own numbers filled in — great for students learning percentage concepts, and for checking the tool itself.
Your Currency, Your Rounding
Nine currencies with correct local grouping (₹1,20,000 the Indian way, $120,000 the American way) and rounding from auto down to 0 decimals. Both are remembered.
Free and Private
No signup, no tracking. Runs entirely in your browser.
How Each Percentage Is Calculated
These are the formulas the calculator uses, with the example numbers shown in its boxes. Every answer on the page shows the same formula with your own numbers.
- What is 15% of 200? 15 ÷ 100 × 200 = 30
- 25 is what percent of 200? 25 ÷ 200 × 100 = 12.5%
- 25 is 10% of what? 25 ÷ (10 ÷ 100) = 250
- Percentage change from 50,000 to 60,000: (60,000 − 50,000) ÷ |50,000| × 100 = 20% (an increase)
- Percentage difference between 10 and 20: |10 − 20| ÷ ((|10| + |20|) ÷ 2) × 100 = 66.666667%
- 200 plus 10%: 200 + (200 × 10 ÷ 100) = 220; 200 minus 10%: 200 − (200 × 10 ÷ 100) = 180
- 2,000 with 25% off: 2,000 − (2,000 × 25 ÷ 100) = 1,500, a saving of 500
- Paid 800 after 20% off: 800 ÷ (1 − 20 ÷ 100) = 1,000 originally
- Add 18% tax to 1,000: 1,000 + (1,000 × 18 ÷ 100) = 1,180; take 18% tax back out of 1,180: 1,180 ÷ (1 + 18 ÷ 100) = 1,000, so the tax was 180
- Scored 425 out of 500: 425 ÷ 500 × 100 = 85%
- Bought at 400, sold at 500: margin (500 − 400) ÷ 500 × 100 = 20%, and markup 25%
- Measured 9.8 when the true value is 9.81: |9.8 − 9.81| ÷ |9.81| × 100 = 0.101937% error
With “Round answers to” on Auto, answers show up to six decimal places; pick a fixed number of decimals to round them.