What’s the difference between x% of y and increasing y by x%?

x% of y returns only the portion; increase y by x% returns the new total after adding that portion to y.

When is the result shown as currency?

Only in shopping modes (discount and original price). Other modes show plain numbers to fit any context.

Why do I see a dash instead of a number?

If a formula would divide by zero or is otherwise undefined, the tool shows a dash so it doesn’t mislead you.

How precise are the outputs?

Results display up to six decimal places to keep rounding predictable. Use the CSV to capture exact values.

Percentage Calculator

Pick a mode, enter your numbers, and get a clean answer with the formula used. Everything runs in your browser.

Overview

Percentages pop up everywhere: shopping discounts, grade changes, price increases, margin improvements, and quick comparisons. This calculator gives you seven common percentage modes so you don’t have to memorize formulas. Choose a mode like “x% of y,” “what percent is x of y,” increase/decrease by a percent, percent change between two values, discount price, or original price before a discount. You’ll get the result instantly and see the exact step used. It’s fast, mobile-friendly, and private because calculations stay in your browser.

You can copy results, download a CSV, or jump to related tools like our Tip Calculator, Sales Tax Calculator, or Compound Interest Calculator when you need more context. Use it for homework, receipts, budget adjustments, or analytics checks.

Mode

Inputs

Percent (%)

Base value

We’ll also show the formula step we used.

Result

Answer	0

How to use this percentage calculator

Pick a mode. Use the chips above to tell the calculator what you want. For example, “x% of y” or “percent change from a to b.”
Enter values. Only the relevant fields show for each mode. Values accept decimals and large numbers.
See the math. The Result card shows key inputs, the direct formula, and the final answer.
Download or share. Click CSV to save inputs and outputs. This is useful for homework steps or audit notes.
Explore related tools. Need taxes or tips? Try the Sales Tax or Tip calculators.

Everything runs locally in your browser for speed and privacy.

Understanding your results

x% of y returns a portion of a base number. What percent is x of y returns a percentage comparison; if the whole is zero, the result is undefined and we show a dash. Increase/decrease applies a percent up or down and displays the change amount so you can see the delta. Percent change measures relative growth or drop from a starting value to an ending value. For shopping, discount gives the final price after subtracting a percent, and original price reverses a discount to find the pre-sale price.

Numbers are shown with up to six decimal places to avoid rounding surprises. In discount modes, answers display as currency; in all other modes, you’ll see plain numbers so you can copy them into any context.

Quick formulas

x% of y → (x/100) × y
x is what % of y → (x / y) × 100
Increase y by x% → y × (1 + x/100)
Decrease y by x% → y × (1 − x/100)
Percent change from a to b → ((b − a)/a) × 100
Discount x% on price p → p × (1 − x/100)
Original price → final ÷ (1 − x/100)

FAQ

What’s the difference between “x% of y” and “increase y by x%”?

x% of y gives a portion only. Increase y by x% returns the new total after adding that portion to y.

Why do some answers show a dash?

If a required value is zero in a way that makes the formula undefined (for example “what percent is x of 0”), we show “—” instead of a misleading number.

When do you show currency?

Only in the shopping modes (discount and original price). Everywhere else we keep it unit-agnostic so you can apply the result to grades, counts, or prices.

How precise are the results?

We display up to six decimal places. If you need fewer, round as needed. The CSV also includes the unrounded values.

Can I link to related tools?

Yes. Use the “Related tools” section below to jump to Tip, Sales Tax, or Compound Interest.