📅 Updated June 12, 2026⏱ 5 min read✍️ By Anchor AI Tools
✓ Free, no signup✓ Percent of a number✓ Percent change✓ Discounts & markups
Work out any percentage instantly — find a percent of a number, figure out what percent one number is of another, or calculate a percentage increase or decrease. This free percentage calculator is fast, mobile-friendly, and useful for pricing, reports, schoolwork, sales, tax, discounts, markups, and everyday percentage math.
Quick Answer: To calculate a percentage, divide the part by the whole and multiply by 100. To find a percentage of a number, divide the percent by 100 and multiply by the number. To calculate percentage change, use ((new value − old value) ÷ old value) × 100.
Percentage Calculator
Choose the percentage calculation you need, enter your numbers, and click calculate. The calculator covers the three most common percentage problems: percent of a number, one number as a percent of another, and percentage increase or decrease.
% Percentage Calculator
Find percentages, percent change, discounts, and markups instantly.
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How to Calculate a Percentage
A percentage is simply a fraction of 100. The word percent means per hundred, so 25% is the same as 25 out of 100, or 0.25. Almost every percentage problem is one of three types, and this calculator solves all three.
1. Finding a percentage of a number
This answers questions like “what is 20% of 150?” It is useful for discounts, tips, tax, commissions, and estimates.
This answers questions like “30 is what percent of 120?” It is useful for test scores, progress, conversion rates, budgets, and comparisons.
Percent = (Part ÷ Whole) × 100
Example: 30 out of 120 → (30 ÷ 120) × 100 = 25%.
3. Percentage increase or decrease
This answers questions like “what is the percentage change from 80 to 100?” It is useful for price changes, growth, losses, weight change, and business reporting.
Change % = ((New − Old) ÷ Old) × 100
Example: 80 → 100 gives ((100 − 80) ÷ 80) × 100 = +25% increase. A negative answer means a decrease.
Quick Percentage Tips
10% of anything: move the decimal one place left. 10% of 240 is 24.
1% of anything: move the decimal two places left. 1% of 240 is 2.4.
15% tip: calculate 10%, then add half of that 10%.
Reverse a discount: if an item is 25% off and costs $60, the original price was $60 ÷ 0.75 = $80.
Percentages can flip: 8% of 50 equals 50% of 8. Both are 4.
Practical answers for percentage increase, decrease, discounts, markups, and percent-of calculations. Use the percentage calculator for quick percentage math in pricing, reports, schoolwork, and business estimates. Use the percentage calculator.
What is a percentage calculator?
A percentage calculator helps calculate percentages, percent change, discounts, markups, and one-number-as-a-percent-of-another problems without manual formula mistakes.
How do I calculate percentage of a number?
To find a percentage of a number, convert the percent to a decimal and multiply. For example, 15% of 200 is 0.15 × 200 = 30.
How do I calculate percentage increase?
Percentage increase shows how much a value went up compared with the original value. Formula: (new value − old value) ÷ old value × 100. The percentage calculator handles the formula instantly.
How do I calculate percentage decrease?
Percentage decrease shows how much a value dropped compared with the original value. Formula: (old value − new value) ÷ old value × 100. This is useful for sales, price drops, losses, and reductions.
How do I find what percent one number is of another?
To find a percentage of a number, convert the percent to a decimal and multiply. For example, 15% of 200 is 0.15 × 200 = 30.
How do I calculate discount percentage?
Discount percentage compares the price reduction with the original price. Formula: discount ÷ original price × 100. To find the sale price, subtract the discount amount from the original price.
How do I add a percentage to a price?
To add a percentage to a price, multiply the price by the percentage as a decimal, then add that amount to the original price. Example: adding 20% to $50 gives $60.
How do I subtract a percentage from a price?
To subtract a percentage from a price, multiply the price by the percentage as a decimal, then subtract that amount. Example: 25% off $80 is $20 off, so the final price is $60.
What is the percentage change formula?
The percentage change formula is (new value − old value) ÷ old value × 100. A positive result is an increase; a negative result is a decrease.
How do I calculate markup percentage?
Markup percentage compares profit with cost. Formula: (selling price − cost) ÷ cost × 100. It is useful for pricing products, services, and project quotes.
⚠️ Accuracy Note: This percentage calculator is provided for general informational and educational purposes. Always double-check important financial figures, tax calculations, payroll values, and business estimates.
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Anchor AI Tools Editorial Team
We build free, fast, and accurate online tools that explain the answer — not just show a number. Used by freelancers, students, marketers, payroll teams, and small businesses every day.
