44available tools
Free, fast utilities available without creating an account.
Category
Mathematics & calculation
Calculate percentages, geometry, unit conversions, and number operations with free tools that run directly in your browser.
44 tools available
4subcategories
Clear families that help you find the right operation quickly.
44embeddable widgets
The same tools ready to embed directly on your own website.
Why this category?
Why use mathematics & calculation tools?
Everyday calculations do not always require a spreadsheet or specialized software. This category groups tools whose main purpose is to produce a numerical result, from percentages and unit conversions to geometry and number operations.
Tools are organized by intent — geometry, percentages, conversions and units, and numbers — so the right operation is easy to find. Future specialized calculators can reuse the same calculation engines when they share an operation, keeping results consistent across pages.
Use cases
Solve a practical calculation
Run conversions, percentage calculations, or numeric operations without a spreadsheet.
Work with geometry
Calculate areas, perimeters, volumes, and other properties of shapes.
Convert units
Switch between measurement units using a shared conversion engine.
Browse by subcategory
All tools
Geometry
Calculate areas, perimeters, volumes, and geometric relationships.
Mathematics & calculation
Geometry calculator
Choose a shape, enter the dimensions you know and instantly calculate everything that can be derived.
100% local
Use this toolMathematics & calculation
Square area calculator
Calculate the area of a square instantly from its side length.
100% localNew
Use this toolMathematics & calculation
Square perimeter calculator
Calculate the perimeter of a square instantly from its side length.
100% localNew
Use this toolMathematics & calculation
Rectangle area calculator
Calculate the area of a rectangle instantly from its length and width.
100% localNew
Use this toolMathematics & calculation
Rectangle perimeter calculator
Calculate the perimeter of a rectangle instantly from its length and width.
100% localNew
Use this toolMathematics & calculation
Triangle area calculator
Calculate the area of a triangle instantly from its base and height.
100% localNew
Use this toolMathematics & calculation
Triangle perimeter calculator
Calculate the perimeter of a triangle instantly from its three side lengths.
100% localNew
Use this toolMathematics & calculation
Circle area calculator
Calculate the area of a circle instantly from its radius.
100% localNew
Use this toolMathematics & calculation
Circle circumference calculator
Calculate the circumference of a circle instantly from its radius.
100% localNew
Use this toolMathematics & calculation
Pythagorean theorem calculator and converse
Calculate a side of a right triangle with the Pythagorean theorem or test whether a triangle is right using its converse.
100% localNew
Use this toolMathematics & calculation
Thales theorem calculator and converse
Calculate a missing length with Thales’ theorem or test parallel lines with its converse.
100% localNew
Use this toolPercentages
Calculate proportions, changes, discounts, and percentages.
Mathematics & calculation
Percentage calculator
Calculate a percentage, a change, or recover an original value.
100% local
Use this toolMathematics & calculation
Calculate X% of a number
Calculate X% of a number instantly, for example 20% of 150.
100% localNew
Use this toolMathematics & calculation
What percentage is X of Y?
Calculate what percentage one value represents of another.
100% localNew
Use this toolMathematics & calculation
Percentage increase calculator
Calculate the percentage increase between an initial value and a final value.
100% localNew
Use this toolMathematics & calculation
Percentage decrease calculator
Calculate the percentage decrease between an initial value and a final value.
100% localNew
Use this toolMathematics & calculation
Discount and sale price calculator
Calculate the final price after a discount and the amount saved instantly.
100% localNew
Use this toolConversions & units
Convert measurement units.
Mathematics & calculation
Universal converter
Instantly convert length, mass, temperature, volume and dozens of other units.
100% local
Use this toolMathematics & calculation
CM ↔ inches converter
Convert centimeters to inches instantly, or switch direction to convert inches to centimeters.
100% localNew
Use this toolMathematics & calculation
KG ↔ lbs converter
Convert kilograms to pounds (lb) instantly, or switch direction to convert pounds to kilograms.
100% localNew
Use this toolMathematics & calculation
MM ↔ inches converter
Convert millimeters to inches instantly, or switch direction to convert inches to millimeters.
100% localNew
Use this toolMathematics & calculation
Celsius ↔ Fahrenheit converter
Convert degrees Celsius to degrees Fahrenheit instantly, or switch direction to convert Fahrenheit to Celsius.
100% localNew
Use this toolMathematics & calculation
KM ↔ miles converter
Convert kilometers to miles instantly, or switch direction to convert miles to kilometers.
100% localNew
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Meters ↔ feet converter
Convert meters to feet or feet to meters instantly.
100% localNew
Use this toolMathematics & calculation
Feet ↔ inches converter
Convert feet to inches or inches to feet instantly.
100% localNew
Use this toolMathematics & calculation
Ounces ↔ grams converter
Convert ounces to grams or grams to ounces instantly.
100% localNew
Use this toolMathematics & calculation
Pounds (lb) ↔ grams converter
Convert pounds (lb) to grams or grams to pounds instantly.
100% localNew
Use this toolMathematics & calculation
Liters ↔ US gallons converter
Convert liters to US gallons or US gallons to liters instantly.
100% localNew
Use this toolMathematics & calculation
Cubic meters ↔ liters converter
Convert cubic meters to liters or liters to cubic meters instantly.
100% localNew
Use this toolMathematics & calculation
KM/H ↔ MPH converter
Convert kilometers per hour to miles per hour or MPH to KM/H instantly.
100% localNew
Use this toolMathematics & calculation
m² ↔ ft² converter
Convert square meters to square feet or square feet to square meters instantly.
100% localNew
Use this toolMathematics & calculation
Hectares ↔ acres converter
Convert hectares to acres or acres to hectares instantly.
100% localNew
Use this toolMathematics & calculation
Liters ↔ UK gallons converter
Convert liters to imperial UK gallons or UK gallons to liters instantly.
100% localNew
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Bar ↔ PSI converter
Convert bar to PSI or PSI to bar instantly.
100% localNew
Use this toolMathematics & calculation
kW ↔ PS ↔ hp converter
Convert kilowatts, metric horsepower (PS) and mechanical horsepower (hp) without treating them as identical.
100% localNew
Use this toolMathematics & calculation
MB/GB ↔ MiB/GiB converter
Convert decimal storage units MB/GB and binary units MiB/GiB correctly.
100% localNew
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Yards ↔ metres converter
Convert yards to metres or metres to yards instantly.
100% localNew
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PSI ↔ kPa converter
Convert PSI to kilopascals or kPa to PSI instantly.
100% localNew
Use this toolMathematics & calculation
Knots ↔ km/h converter
Convert knots to kilometres per hour or km/h to knots instantly.
100% localNew
Use this toolMathematics & calculation
kWh ↔ joules converter
Convert kilowatt-hours to joules or joules to kWh instantly.
100% localNew
Use this toolNumbers & calculation
Work with number bases, numbers in words, and random numbers.
Mathematics & calculation
Random number generator
Generate one or more random numbers using the range and quantity you choose.
100% local
Use this toolMathematics & calculation
Number base converter
Convert whole numbers between bases 2 and 36, including binary, octal, decimal and hexadecimal.
100% local
Use this toolMathematics & calculation
Number ↔ words
Convert a number to words or written words back to digits, with a euro amount mode for cheques and documents.
100% localNew
Use this toolMathematics & calculation
Cheque / check amount in words
Write a euro amount in words for a cheque or check, with euros and cents handled automatically.
100% localNew
Use this toolAll these tools are also available as widgets
Add tools from this category to WordPress, Webflow, Wix, or any HTML page with the same local processing.
Frequently asked questions
Do calculations run locally?
Yes. The relevant tools perform calculations directly in your browser.
Do these results replace professional advice?
No. They provide practical calculations; regulated or professional uses should be checked for your context.
Can I use these tools for free?
Yes. Public tools in this category are available without an account.