Unit converters with exact factors

Twenty calculators that convert while you type. Most accept several units at once and add them up first — enter 5 ft and 9 in, or 2 lb and 6 oz, and read one answer in every other unit.

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All converters

20
Everyday
Mass kilograms, pounds, tonnes, ounces 1 kg = 2.20462 lb Length metres, feet, inches, miles 1 m = 3.28084 ft Area square metres, acres, hectares 1 m² = 10.7639 ft² Volume litres, gallons, cubic metres, cups 1 l = 0.264172 US gal Time seconds, hours, days, years 1 h = 60 min Temperature Celsius, Fahrenheit, Kelvin 100 °C = 212 °F Speed km/h, mph, m/s, knots 1 km/h = 0.621371 mph
Engineering
Pressure bar, psi, pascal, atmospheres 1 bar = 14.5038 psi Energy joules, calories, kWh, BTU 1 kJ = 0.239006 kcal Power watts, kilowatts, horsepower 1 kW = 1.34102 hp Force newtons, kilogram-force, pound-force 1 N = 0.101972 kgf Torquenew newton-metres, lb-ft, kgf·m 1 N·m = 0.737562 lbf·ft Flow rate l/s, m³/h, gallons per minute 1 l/s = 3.6 m³/h Densitynew kg/m³, g/cm³, lb/ft³ 1 kg/m³ = 0.001 g/cm³ Frequency hertz, kilohertz, RPM 1 Hz = 0.001 kHz
Digital & other
Digital storagenew MB, GB, TB, mebibytes 1 MB = 0.001 GB Data transfer ratenew Mbit/s, MB/s, Gbit/s 1 Mbit/s = 0.125 MB/s Number scale thousands, millions, billions 1 millions = 1 000 thousands Anglenew degrees, radians, gradians 1 ° = 0.0174533 rad Fuel economynew l/100 km, MPG, km/l 8 l/100 km = 29.4018 MPG (US)
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Why the fields add up

Real measurements arrive in pieces. Heights come as feet and inches, weights as pounds and ounces, durations as hours and minutes. A converter that takes one number per go makes you do the joining by hand, which is where mistakes creep in. Here every filled field feeds the same total, and every output is that total expressed in one more unit.

Exact factors, printed on the page

Each converter lists the exact equalities it uses — 1 in = 25.4 mm, 1 lb = 0.45359237 kg, 1 atm = 101 325 Pa, 1 kcal = 4184 J — plus the formula itself, so you can check a result by hand or reuse the constant in a spreadsheet. Where a unit is genuinely approximate (an averaged month, Mach at sea level, metric versus mechanical horsepower) the page says so instead of pretending.

Straight answers, no accounts

Nothing is stored, nothing is sent anywhere, no sign-up is asked for. The whole calculation runs in your browser, so pages work offline once loaded and stay quick on a phone. Precision is adjustable from 4 to 12 significant figures, and clicking any result copies it to the clipboard.

Questions

Do I have to press a button?

No. Results update while you type. The Convert button is there if you prefer it, and Clear empties the form.

Can I enter a comma as the decimal separator?

Yes. 3,5 and 3.5 are both read as three and a half.

How do I copy a result?

Click the result field. It copies the plain value with its unit, without the thousands spacing.

How accurate are the results?

Factors are the exact international definitions, and calculations run in double precision. Displayed digits are your choice, from 4 to 12 significant figures.

Does it work on a phone?

Yes — the layout collapses to a single column and the inputs open a numeric keypad.