How do you calculate a percentage?
20 ÷ 100 × 150 = 30
Find a share, work out a discount, and understand percentage change.
See the steps →A little clarity. A better decision.
Everyday questions.
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20% of 150
Calculation20 ÷ 100 × 150 = 30
Percentage calculations are universal — same formula everywhere. Full calculator →
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Percentage calculator
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20% of 150 = 30
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Visit the learning hub →Worked examples make formulas easier to use again. Start with these everyday questions.
How do you add fractions?
1/2 + 1/3 = 3/6 + 2/6 = 5/6
Find a common denominator and convert between fractions and decimals.
See the steps →Which operation comes first?
2 + 3 × 4 = 14
Use brackets, powers, multiplication and division before addition and subtraction.
See the steps →A few useful answers
Using our calculators
Learn what a result means and when to check its assumptions.
Which free online calculator should I use?
Choose a calculator for the result you need: percentage for a share or change, mortgage for loan payments, compound interest for savings growth, or take-home pay for estimated net income. Check the units, country, and assumptions before comparing results.
How do I calculate a percentage of a number?
Divide the percentage by 100, then multiply by the number. For example, 20% of 150 is 20 ÷ 100 × 150 = 30. Use the percentage calculator to find a share, a percentage change, or a percentage difference.
What is the difference between percentage change and percentage points?
Percentage change measures the change relative to the original value: (new − original) ÷ original × 100. Percentage points are the direct difference between two percentages. A rate rising from 10% to 15% increases by 5 percentage points, or 50% relative to its original value.
Why do some calculators ask for my country?
A mathematical formula can be universal while its inputs and interpretation vary. Income tax bands, payroll deductions, currency conventions, and some health reference standards depend on the country. Select the matching country and review the assumptions on the calculator page.
Are calculator results exact?
Arithmetic results use standard formulas and are rounded for display. Financial projections and health results are estimates based on the inputs and assumptions shown. Tax rules, interest conventions, and personal circumstances can affect the real result; read the methodology and sources on the relevant page.
Do I need an account to use these calculators?
No. The calculators are free to use without an account. Calculations run in your browser. Some tools, such as currency conversion, may request reference data; the privacy policy explains how the site handles data.
Which tax year does the salary calculator use?
Use the tax year and data notes displayed on the specific calculator. Fiscal years differ by country, and a page update does not necessarily mean its underlying tax data has been refreshed. Check the listed exclusions before using an estimate for budgeting.