How to Calculate Percentages — Complete Guide

2026-07-25· タグ: percentage-calculator, math-guide, percent-formula, business-math

Basic Percentage Formulas

Percentage of a number: X × Y ÷ 100 = Result Example: 15% of 200 = 200 × 15 ÷ 100 = 30

What percent is X of Y: X ÷ Y × 100 = Percentage Example: 30 ÷ 200 × 100 = 15%

Percentage increase/decrease: X ± (X × Y ÷ 100) = Result

Percentages are everywhere: sales tax (8.5%), tips (15-20%), discounts (30% off), interest rates (5% APR), and statistical reports.