Three common percentage calculations in one place
Percentage math shows up constantly in everyday and business situations — figuring out a discount at checkout, working out what portion of a budget has been spent, or pricing a product with a healthy markup over cost. This tool covers the three most commonly needed calculations side by side, so there's no need to remember which formula to rearrange for each one.
The three calculators explained
- What is X% of Y? — finds a portion of a number. Useful for calculating a tip, a discount amount, or a percentage-based fee.
- X is what % of Y? — finds the percentage relationship between two numbers. Useful for tracking what portion of a goal has been reached, or comparing two values.
- Markup calculator — adds a percentage on top of a cost to find a sale price. Useful for anyone pricing a product or service based on what it costs to provide.
Markup versus margin — a common mix-up
These two terms get confused often, but they're calculated differently. Markup is a percentage added on top of cost — a $100 item with a 30% markup sells for $130. Margin is the profit expressed as a percentage of the selling price instead — on that same $130 sale, the $30 profit is only about 23% of the final price, not 30%. This calculator specifically works out markup (cost-based), which is what most small businesses use when pricing from a known cost.
Your numbers stay private
Nothing you enter into this calculator is sent anywhere — every calculation runs directly in your browser. See our Privacy Policy for full details.
A quick worked example
Say an item is priced at $150 and is 20% off. Using the "What is X% of Y?" calculator with X as 20 and Y as 150 gives a discount amount of $30 — so the final price is $150 minus $30, or $120. Flip it around with the second calculator to check your work: $30 is exactly 20% of $150, confirming the discount was applied correctly. The same pattern works for tips, sales tax, or any other situation where you need to find a portion of a total.
Frequently asked questions
+Is this percentage calculator really free, with no sign up?
Yes. There's no account and no limit on how many calculations you can do.
+What's the difference between the three calculators on this page?
"What is X% of Y?" finds a portion of a number — useful for discounts or tips. "X is what % of Y?" finds the percentage relationship between two numbers — useful for tracking progress or comparing values. "Markup" adds a percentage on top of a cost to find a sale price — useful for pricing something you're reselling.
+How do I calculate a discount using this tool?
Use the "What is X% of Y?" calculator with the discount percentage as X and the original price as Y — that gives you the discount amount. Subtract that from the original price to get the final sale price.
+What's the difference between markup and margin?
Markup is calculated as a percentage of the cost (what this tool calculates), while margin is calculated as a percentage of the final selling price. A 30% markup on a $100 cost gives a $130 price, but that $30 profit is only about 23% of the $130 selling price — margin and markup are related but not the same number.
+Is my data sent anywhere when I use this?
No. Every calculation happens directly in your browser — nothing you enter is uploaded or stored.