If a price goes up 50% then down 50%, am I back where I started?

No — you end up 25% lower. Percent change is always taken from the current value, so +50% of 100 is 150, then −50% of 150 is 75. Successive percentages don't cancel out.

What's the difference between "percent" and "percentage points"?

If a rate moves from 2% to 3%, that's one percentage point but a 50% increase in the rate. The percent-change card gives you +50%; the percentage-point gap is just plain subtraction (3 − 2 = 1).

Which card do I use for a discount?

Use "What is X% of a number" — enter the discount percent and the price to get the amount off (25% of 80 = 20), then subtract that from the price. Or use the percent-change card with the old and new prices to confirm the discount.

How precise are the answers?

Results are rounded to three decimal places and formatted with thousands separators. An empty input counts as 0, and a calculation that would divide by zero shows a dash instead of a number.

Do I need to press a calculate button?

No — all three cards update live as you type, and they start pre-filled with example numbers so you can see how each one works. Nothing is uploaded, and it runs offline.

Percentage Calculator

Find X% of a number, what percent one value is of another, and percent change.

% of a number

Percent (%)Value

Result

X is what % of Y

NumberValue

Result

12.5%

Percent change

FromTo

Result

+50%

What is Percentage Calculator?

Percentage Calculator answers the three percentage questions people search for most: what is X% of a number, X is what percent of Y, and percent increase or decrease between two values. Type the numbers and the answer updates instantly. It's a free percentage calculator that runs in your browser and works offline.

Key features

What is X% of a number — tips, discounts, tax
X is what percent of Y — scores and shares
Percent change shown with + and − signs
Answers update live as you type
Copy the result with one click

Percentage Calculator — the three calculations you actually need

Most "percentage calculator" searches are really one of three specific questions, and this tool lays out all three at once as separate cards — so you don't have to pick a mode, and you can read whichever answer you need. Everything is plain arithmetic done in your browser; the numbers you type are never sent anywhere, and it works offline.

1. What is X% of a number?

Enter a percentage and a value. 15% of 200 = 30. This is the tip / tax / discount / commission card: 18% gratuity on a 60,000-won bill, 10% VAT on a price, a 25%-off sale, a 3% sales commission. The math is value × percent ÷ 100.

2. X is what percent of Y?

Enter two numbers to get the first as a percentage of the second. 25 is 12.5% of 200. Use it for a test score (43 out of 50), a completion rate (18 of 30 tasks done), or one line item's share of a total. The math is X ÷ Y × 100.

3. Percent change (increase or decrease)

Enter a starting value and an ending value. The result is signed — + for an increase, − for a decrease — and color-coded. 100 → 150 is +50%; 100 → 50 is −50%. This is the card for price moves, growth rates, and any before/after comparison. The math is (to − from) ÷ from × 100.

The gotcha that trips everyone up

Percent change is always measured against the original value, and that has a consequence people get wrong constantly: a 50% rise followed by a 50% fall does not return you to the start. Go up 50% from 100 and you're at 150; drop 50% of 150 and you land at 75, not 100. Successive percentages don't add — each is taken from the new base. The same logic means a stock that falls 50% has to rise 100% just to break even.

Percent vs. percentage points

Another common mix-up: if an interest rate goes from 2% to 3%, that's a rise of one percentage point but a 50% increase in the rate. Card 3 gives you the percentage change (+50%); the "percentage point" difference is just plain subtraction (3 − 2 = 1). Be clear about which one a question is asking for before you quote a number.

Reading the results

All three cards start pre-filled with example numbers so you can see the shape of each calculation, and they recompute live as you type — there's no calculate button. Results are rounded to three decimal places and shown with thousands separators, an empty field is treated as 0, and a calculation that would divide by zero shows a dash. Copy any answer straight from the highlighted result.

Frequently asked questions

If a price goes up 50% then down 50%, am I back where I started?: No — you end up 25% lower. Percent change is always taken from the current value, so +50% of 100 is 150, then −50% of 150 is 75. Successive percentages don't cancel out.
What's the difference between "percent" and "percentage points"?: If a rate moves from 2% to 3%, that's one percentage point but a 50% increase in the rate. The percent-change card gives you +50%; the percentage-point gap is just plain subtraction (3 − 2 = 1).
Which card do I use for a discount?: Use "What is X% of a number" — enter the discount percent and the price to get the amount off (25% of 80 = 20), then subtract that from the price. Or use the percent-change card with the old and new prices to confirm the discount.
How precise are the answers?: Results are rounded to three decimal places and formatted with thousands separators. An empty input counts as 0, and a calculation that would divide by zero shows a dash instead of a number.
Do I need to press a calculate button?: No — all three cards update live as you type, and they start pre-filled with example numbers so you can see how each one works. Nothing is uploaded, and it runs offline.

Privacy

Every calculation is local arithmetic; the numbers you enter are never sent to a server.