Common hub
Everyday unit converters for length, weight, temperature, and more.
About common conversions
Common unit converters cover the measurements you reach for every day — length, weight, temperature, area, volume and speed. Whether you're translating meters to feet for a DIY project, converting kilograms to pounds at the gym, or figuring out the difference between Celsius and Fahrenheit, these tools deliver instant, accurate answers grounded in international SI definitions. Every converter on this page uses the canonical conversion factor (no rounding shortcuts) and works on mobile in a single tap.
What's hot in common
The most-launched tools in this category this week.
All common tools
Every converter and calculator in this hub, ready to launch.
Length Converter
Convert meters, feet, miles, kilometers, inches, yards and more.
Weight Converter
Convert kilograms, pounds, ounces, stones, grams, tons and more.
Temperature Converter
Convert Celsius, Fahrenheit, Kelvin and Rankine instantly.
Area Converter
Convert square meters, acres, hectares, square feet and more.
Volume Converter
Convert liters, gallons, cups, pints, milliliters and more.
Speed Converter
Convert km/h, mph, m/s, knots and Mach.
Popular common conversions
The most-searched conversion pairs — one tap straight to the answer.
When you'll reach for these
Practical scenarios where this hub shines.
Travel between countries
Mile/kilometre, °F/°C and pound/kilogram all in one tap so road signs and weather forecasts make instant sense.
DIY & home projects
Translate hardware specs and lumber sizes between imperial and metric without a calculator.
International shopping
Compare clothes, packages and weights across US, UK and EU listings with confidence.
Key formulas
- Meters → Feet
ft = m × 3.28084 - Celsius → Fahrenheit
°F = °C × 9/5 + 32 - Kilograms → Pounds
lb = kg × 2.20462
Common mistakes
Mixing US and UK gallons
1 US gallon ≈ 3.785 L; 1 UK (imperial) gallon ≈ 4.546 L — a 20% difference that ruins recipes and fuel-economy comparisons.
Treating Celsius as linear with Fahrenheit
°F has an offset, not just a scale factor. Use the formula °F = °C × 9/5 + 32, not a simple multiply.
Did you know?
−40°C equals −40°F
The two scales intersect exactly once — at minus forty degrees.
The metre is defined by light
Since 1983, a metre is the distance light travels in a vacuum in 1/299,792,458 of a second.
Frequently asked
Which conversion is the most searched online?
Meters to feet, kilograms to pounds, and Celsius to Fahrenheit consistently rank as the most searched conversions worldwide.
Are these conversions accurate enough for engineering work?
Yes — we use the exact international definitions (e.g. 1 inch = 0.0254 m exactly), so results match what you'd compute by hand or in CAD software.
Why is 1 mile not a round number of kilometers?
Because the mile was historically defined by Roman paces and later standardized to exactly 1,609.344 meters when the imperial system was harmonized.
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