MathsLive

Unit Converter

Pick a category, enter a value and choose what to convert from and to.

Short answer

Length and weight conversions multiply by a fixed factor. Temperature uses formulas: °F = °C × 9/5 + 32, K = °C + 273.15.

Conversion

Calculation method, coverage and version

Inputs used: Category, Value, From unit, To unit.
Calculation approach: The calculator applies the rules and assumptions described in “How it works” to the values you enter. Rounding can cause small differences from an official or provider calculation.
Coverage: Maths. UK nations, tax treatment, local rules and provider criteria can differ; check the official sources shown below before acting.
Content version: No page-specific review date is currently published. Treat the result as indicative and verify current rules independently.

Not included unless explicitly requested: personal circumstances not entered, provider discretion, future rule changes, professional fees and case-specific exceptions. Read the full calculator methodology.

How it works

Length and weight: each unit has a fixed multiplier to a base unit (metres or kilograms). Convert by going to the base then to the target. Temperature uses simple formulas because the scales have different zero points.

Worked example

100 km to miles: 100 × 1000 m ÷ 1609.344 m/mi ≈ 62.137 mi.

20°C to °F: 20 × 9/5 + 32 = 68°F.

Who should use this

•UK shoppers reading US recipes
•Travellers
•Anyone working with mixed unit systems

Common mistakes

×Mixing up oz (avoirdupois weight) and fl oz (fluid volume)
×Forgetting that stones are 14 lb each

Frequently asked questions

Why isn't volume here?▾

Volume conversions (cups vs ml etc) depend on the country and substance. We'll add it as a separate tool.

Related calculators

Percentage Calculator →Square Footage →