Calculate X% of Y, what percent one number is of another, plus profit margin and markup from cost and sell price—all in your browser. Four focused modes, instant results, no login—ideal for grades, discounts, retail pricing, and quick ratio checks.
Four modes: (1) X% of Y — enter a percentage and a base number to get the portion; (2) X is what percent of Y — enter a part and a whole to get the percentage; (3) Profit margin — enter cost and sell price to get margin % = (sell−cost)/sell×100 plus profit; (4) Markup — enter cost and sell to get markup % = (sell−cost)/cost×100 plus profit. Switch modes with the dropdown before calculating.
Select the "X% of Y" mode. Enter 15 in the percent field and 200 in the base field, then click Calculate. The result is 30—the tool computes (15 ÷ 100) × 200.
Select "X is what percent of Y" mode. Enter 42 as the part and 50 as the whole. The result is 84%, computed as (42 ÷ 50) × 100. The whole cannot be zero.
Yes, in two steps. First find the discount amount with "X% of Y" (e.g., 20% of 80 = 16). Subtract manually, or enter the remaining percent (80% of 80 = 64) using the same mode with the post-discount percentage.
For increase: compute new−old, then use "X is what percent of Y" with the difference as X and the old value as Y. Absolute difference is new−old; relative change is that difference as a percent of the baseline. Dedicated increase/difference modes are not built in yet—use the two core percent modes in sequence.
Choose Profit margin mode. Enter cost and sell price. Margin % = (sell − cost) ÷ sell × 100, and profit = sell − cost. Sell price must be greater than zero; sell cannot be less than cost. Example: cost 40, sell 50 → profit 10, margin 20%.
Markup divides profit by cost: markup % = (sell − cost) ÷ cost × 100. Margin divides by sell price. Same numbers (cost 40, sell 50) give markup 25% but margin 20%. Use Markup mode when pricing from cost; use Margin when reporting profit as a share of revenue.
Results display up to four decimal places, trailing zeros removed—for example 33.3333% instead of a long repeating fraction. Financial compliance workflows may require banker's rounding elsewhere.
In "what percent" mode, dividing by zero is undefined. The tool shows an error instead of a result. Check that your whole (Y) value is greater than zero. Margin rejects sell ≤ 0; markup rejects cost ≤ 0.
No. Calculations run entirely in your browser. Amounts and percentages never leave your device.
Use Percentage Calculator for general percent-of, ratio, margin, and markup math. Tip Calculator adds bill-splitting, tip presets, and dining-specific defaults on Power Tools.
Yes. Free with no login required.