What is X% of Y Calculator

How to use the “What is X% of Y” calculator

Enter the percentage in the Percent field and the number in the Number field. The result updates instantly as you type — no button to press. For example, to find 15% of $800, type 15 in the Percent field and 800 in the Number field. The calculator returns 120. You can use decimals in either field: 0.5% of 1,000,000 gives you 5,000. The result is always displayed with full comma formatting so large numbers stay readable.

How the calculator works

The formula is: Result = (X ÷ 100) × Y. Divide the percentage by 100 to convert it to a decimal, then multiply by the target number. For example, 20% of 500 is (20 ÷ 100) × 500 = 0.20 × 500 = 100. This single formula is the foundation of most real-world percentage math — discounts, tax amounts, tip calculations, investment returns, commission payouts, and ownership stakes all reduce to this same operation.

When to use this calculator

This calculator handles any situation where you need to find a portion of a total. Common uses include: finding a discount amount before it appears at checkout (20% off $75 = $15 savings); calculating a tip on a restaurant bill (18% of $62 = $11.16); figuring out sales tax (8.5% of $120 = $10.20); computing a commission on a sale (5% of $4,000 = $200); and sizing a position in stocks or crypto (2% of a $10,000 portfolio = $200 risk per trade). Any time you know the rate and the base number, this calculator gives you the amount instantly.

Frequently asked questions