How this tool works
Tools are grouped by the task they solve rather than multiplied into separate pages for every direction. Most converters accept input in either unit.
Home / Maintained tool directory
All Tools
A curated directory of the calculators we actively maintain and test. Retired single-direction pages now lead to their more capable replacement.
Length converterEight metric and imperial units in either direction.Inches and millimetresExact decimals plus a practical fractional result.Fractional inchesChoose precision from 1/2 to 1/64 inch.Weight converterKilograms, pounds, stone, ounces and grams.Temperature converterCelsius, Fahrenheit and Kelvin with offsets.Speed convertermph, km/h, knots, m/s and ft/s.Cooking and volumeExplicit US, UK and metric measures.Area converterSquare units, acres and hectares.Time converterSeconds through weeks without month ambiguity.Hours to daysCalendar days and configurable working days.Annual leave calculatorConvert leave hours using your own schedule.Work-hours calculatorShifts, breaks, overtime and estimated pay.Data storageCorrect GB/GiB and TB/TiB distinctions.Batch converterConvert lists and download CSV results.Currency converterLive exchange-rate conversion.Roman numeralsConvert in both directions from 1 to 3,999.Password generatorCreate strong passwords locally in the browser.Random number generatorChoose a range and generate values.Typing speed testMeasure WPM and accuracy.
When it is useful
Start with a category tool for ordinary measurement, or use a workflow calculator for employment time, batch data, cooking standards or fractional tolerances.
Accuracy and unit standards
Conversion factors and assumptions are stated on each page. If you find a reproducible error, send the page, input and expected result through the contact form.