Percentage Calculator

What Is a Percentage?

A percentage is a number or ratio expressed as a fraction of 100. The word comes from the Latin per centum, meaning "by the hundred." Percentages are one of the most universally used mathematical concepts in everyday life — from calculating discounts at a store to understanding tax rates, exam scores, interest rates, and statistical data. The Toolsiro Percentage Calculator solves four of the most common percentage problems in one place, with a quick-reference table for instant calculations.

The Four Percentage Calculations

1. What is X% of Y?
The most common percentage question. Formula: result = (X ÷ 100) × Y. Examples: What is 20% of 500? Answer: 100. What is 8.5% of 1,200? Answer: 102. Used for: calculating discounts, tips, tax amounts, commission, and interest payments.

2. X is what percentage of Y?
Find what percentage one number represents of another. Formula: percentage = (X ÷ Y) × 100. Examples: 45 is what percentage of 180? Answer: 25%. Used for: calculating exam scores, market share, completion rates, and food nutrition percentages.

3. Percentage change (increase or decrease)
Calculate how much a value has increased or decreased as a percentage. Formula: change = ((new − old) ÷ |old|) × 100. Examples: A product price went from 80 to 100 — that is a 25% increase. A salary dropped from 5,000 to 4,500 — that is a 10% decrease. Used for: tracking price changes, measuring growth, comparing performance over time.

4. Add or subtract a percentage from a value
Apply a percentage increase or decrease to a starting value. Formula: result = value × (1 + percentage/100) for increase, or value × (1 − percentage/100) for decrease. Examples: 200 + 15% = 230. 500 − 20% = 400. Used for: applying VAT, calculating sale prices, adding markup, or computing net salary after deductions.

Percentage in Daily Life — Common Uses

• Shopping discounts: A 30% off sale on a SAR 450 item saves SAR 135, making the final price SAR 315. Use calculation 1 (30% of 450) or calculation 4 (450 − 30%).
• VAT and taxes: Saudi Arabia's VAT rate is 15%. Adding 15% VAT to a SAR 100 item gives SAR 115 (calculation 4). To find the pre-VAT price from the total: SAR 115 ÷ 1.15 = SAR 100.
• Exam and test scores: Scoring 68 out of 80 on a test: 68 is what percentage of 80? Answer: 85% (calculation 2).
• Investment returns: A portfolio worth USD 50,000 grew to USD 57,500. The percentage increase: (57,500 − 50,000) ÷ 50,000 × 100 = 15% return (calculation 3).
• Nutrition labels: A food item contains 12g of fat. The daily recommended fat intake is 65g. 12 is what percentage of 65? Answer: 18.5% of daily value (calculation 2).
• Salary increases: Annual salary of EGP 12,000 with a 10% raise: 12,000 + 10% = EGP 13,200 (calculation 4).

Common Percentage Mistakes to Avoid

• Percentages are not symmetric: A 20% increase followed by a 20% decrease does not return to the original value. Starting at 100: +20% = 120, then −20% of 120 = 96 — a net decrease of 4%.
• Percentage points vs percentages: If an interest rate rises from 4% to 6%, it has increased by 2 percentage points, but by 50% in relative terms. These are very different statements.
• Base confusion: "20% off" and "20% added to the discounted price" do not cancel out. A SAR 100 item discounted 20% costs SAR 80. Adding 20% back: 80 × 1.2 = SAR 96, not SAR 100.

Related Calculators

For financial percentage calculations with loan amounts, use the Loan Calculator. For currency percentage differences, combine this tool with the Currency Converter.