7 tools

Math calculators

Calculators for the maths that comes up at school, at work and when shopping.

Percentages, fractions, averages, ratios, LCM and standard deviation, with the working shown for every answer.

Math calculators — editorial still life representing the tools in this category. — 7 math tools — each with formula, worked example and FAQs.

✓ Each answer shows the steps
✓ Decimals and negative numbers accepted where they make sense
✓ Useful for homework, reports and price checks

Percentage Calculator

What is X% of Y? What % is X of Y? Answered with steps.

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Percentage Increase / Decrease Calculator

Old → new percent change, with increase vs decrease explained.

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Fraction Calculator

Add, subtract, multiply, divide and simplify fractions exactly.

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Average Calculator

Mean, median, range and count — paste any number list.

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Standard Deviation Calculator

Sample and population standard deviation, variance and mean for any list of numbers.

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LCM & GCF Calculator

Least common multiple and greatest common factor of up to 20 numbers, with Euclid's steps.

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Ratio Calculator

Simplify ratios, solve proportions (a:b = c:x) and split a total in any ratio.

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How to get the most from math tools

Each math calculator has the same layout: the calculator at the top, then the formula, a worked example, common uses, tips, mistakes to avoid and the sources we used. Run your own numbers first, then use the related calculators at the bottom of the page to check from another angle, such as GST alongside Discount, or Age alongside Date Difference.

Calculations run in your browser, so the numbers you enter are not sent anywhere. If a figure is going into a contract, tax return or medical record, check it against the official source linked on the calculator page.

Common questions

Percentages for shares and growth, Percentage Change for before/after, Fractions for exact parts, Average and Standard Deviation for data, LCM & GCF for factors and multiples, Ratio for proportions and splits. Each page guides you from question to mode.

Other categories

BMI Calculator

Know your Body Mass Index in seconds — with healthy-range context.

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time and-date#02

Age Calculator

Exact age in years, months, days — plus totals and next birthday.

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time and-date#03

Date Difference Calculator

Days between dates — with weekdays, weekends and inclusive counts.

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