Percentage Calculator

How to use

1. X% of Y: Enter percentage and the base value, then Calculate.
2. Percentage Change: Enter old value and new value to see % increase/decrease.
3. What percent is A of B: Enter part (A) and whole (B) to get A as % of B.

Formulas

• X% of Y = (X / 100) × Y
• Percentage change = ((new − old) / old) × 100
• A as % of B = (A / B) × 100

Tips

• For discounts, compute X% of price first, then subtract from price.
• If B = 0, “A of B” is undefined — the tool will ask for valid inputs.