Unit Converter

Convert between metric and imperial units of length, weight, volume, and area. Instant, in-browser, no signup.

How unit conversion works

Each unit has a fixed ratio to a category-defined base unit (meters for length, kilograms for weight, liters for volume, square meters for area). To convert from unit A to unit B in the same category, we go through the base: result = value × A.toBase ÷ B.toBase.

All conversion factors here come from internationally agreed definitions (e.g., 1 inch = 0.0254 m exactly, 1 lb = 0.45359237 kg exactly, 1 US gallon = 3.785411784 L exactly). UK and US gallons are different — pay attention to which one you need.

Note: temperature is not a simple ratio (zero points differ), so it lives on its own page.

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Frequently asked questions

What unit categories does this support?

Length (mm/cm/m/km/in/ft/yd/mi), Weight (mg/g/kg/t/oz/lb/st/US ton), Volume (mL/L/tsp/tbsp/floz/cup/pt/qt/US gal/UK gal), Area (m²/km²/ha/ft²/yd²/acre/mi²). Pick a category, enter a value, choose units.

Are these conversion rates exact?

Length, weight, area are exact international definitions. Volume uses US customary measures with 6 significant digits — common in cooking and casual measurements. For lab-grade precision, use SI units directly.

Does this support currency conversion?

Not yet — currency converter is on the roadmap. Currency requires live exchange rates from a real-time API. For now, search "USD to EUR" in any browser for current rates.