Unit Conversions – Free, Online, Private
Thirty high-traffic unit conversions, each with the exact factor, a converter, a table, worked examples, and the pitfalls that change the result.
- cm to inches converterinches = centimeters ÷ 2.54
- inches to cm convertercentimeters = inches × 2.54
- kg to lbs converterpounds = kilograms ÷ 0.45359237
- lbs to kg converterkilograms = pounds × 0.45359237
- celsius to fahrenheit converter°F = °C × 9/5 + 32
- fahrenheit to celsius converter°C = (°F − 32) × 5/9
- km to miles convertermiles = kilometers ÷ 1.609344
- miles to km converterkilometers = miles × 1.609344
- feet to meters convertermeters = feet × 0.3048
- meters to feet converterfeet = meters ÷ 0.3048
- mm to inches converterinches = millimeters ÷ 25.4
- oz to grams convertergrams = ounces × 28.349523125
- grams to oz converterounces = grams ÷ 28.349523125
- liters to gallons converterUS gallons = liters ÷ 3.785411784
- gallons to liters converterliters = US gallons × 3.785411784
- ml to oz converterUS fl oz = milliliters ÷ 29.5735295625
- mph to km/h converterkm/h = mph × 1.609344
- km/h to mph convertermph = km/h ÷ 1.609344
- mb to gb converterGB = MB ÷ 1000
- gb to mb converterMB = GB × 1000
- kb to mb converterMB = KB ÷ 1000
- bytes to bits converterbits = bytes × 8
- feet to cm convertercentimeters = feet × 30.48
- cm to feet converterfeet = centimeters ÷ 30.48
- stone to kg converterkilograms = stone × 6.35029318
- kg to stone converterstone = kilograms ÷ 6.35029318
- square feet to square meters convertersquare meters = square feet × 0.09290304
- acres to hectares converterhectares = acres × 0.40468564224
- kelvin to celsius converter°C = K − 273.15
- psi to bar converterbar = psi × (6894.757293168361 ÷ 100000)
What these pages are
Each page converts one pair and the reverse, when the reverse has its own URL. The box calls the same factors as the unit converter, so 10 cm is 3.937 inches here and there. The formula on the page is the definition, not a rounded rule of thumb: 2.54 centimetres to the inch, 0.45359237 kilograms to the pound, 9/5 plus 32 for Fahrenheit, 1000 decimal megabytes to the gigabyte. The table rounds for reading. The full-precision line keeps the digits you need if the result is going into another formula.
Length, weight, temperature, volume, speed, data size, area, and pressure are split on purpose. A foot does not become a square foot by wishing. A fluid ounce does not become a weight ounce. A US gallon is not an imperial gallon. Those traps are written on the pair that attracts them, because a hub cannot say all of them in one paragraph and still be believed.
How the factors are chosen
SI and international definitions win. The inch is 25.4 mm, the foot is 0.3048 m, the mile is 1.609344 km, the pound is 0.45359237 kg, and the stone is 14 of those pounds. The US liquid gallon is 3.785411784 litres. The US fluid ounce is that gallon divided by 128. Decimal byte prefixes are powers of 1000. Binary prefixes, KiB and MiB and GiB, are in the unit converter and are not what the MB page divides by. Temperature readings use the offset. Temperature differences do not. PSI converts through the pascal, using standard gravity, so the bar result matches the pressure category.
A swap follows the reverse page when one exists and keeps the number you typed. Pairs without a reverse page swap in place, so the URL stays the one you opened and the units flip. The general unit converter remains the place to leave the pair and try a neighbor that does not have its own page, such as yards, knots, or the imperial gallon.
The pairs
Centimeters to Inches: inches = centimeters ÷ 2.54. Inches to Centimeters: centimeters = inches × 2.54. Kilograms to Pounds: pounds = kilograms ÷ 0.45359237. Pounds to Kilograms: kilograms = pounds × 0.45359237. Celsius to Fahrenheit: °F = °C × 9/5 + 32. Fahrenheit to Celsius: °C = (°F − 32) × 5/9. Kilometers to Miles: miles = kilometers ÷ 1.609344. Miles to Kilometers: kilometers = miles × 1.609344. Feet to Meters: meters = feet × 0.3048. Meters to Feet: feet = meters ÷ 0.3048. Millimeters to Inches: inches = millimeters ÷ 25.4. Ounces to Grams: grams = ounces × 28.349523125. Grams to Ounces: ounces = grams ÷ 28.349523125. Liters to US gallons: US gallons = liters ÷ 3.785411784. US gallons to Liters: liters = US gallons × 3.785411784. Milliliters to US fluid ounces: US fl oz = milliliters ÷ 29.5735295625. Miles per hour to Kilometers per hour: km/h = mph × 1.609344. Kilometers per hour to Miles per hour: mph = km/h ÷ 1.609344. Megabytes to Gigabytes: GB = MB ÷ 1000. Gigabytes to Megabytes: MB = GB × 1000. Kilobytes to Megabytes: MB = KB ÷ 1000. Bytes to Bits: bits = bytes × 8. Feet to Centimeters: centimeters = feet × 30.48. Centimeters to Feet: feet = centimeters ÷ 30.48. Stone to Kilograms: kilograms = stone × 6.35029318. Kilograms to Stone: stone = kilograms ÷ 6.35029318. Square feet to Square meters: square meters = square feet × 0.09290304. Acres to Hectares: hectares = acres × 0.40468564224. Kelvin to Celsius: °C = K − 273.15. Pounds per square inch to Bar: bar = psi × (6894.757293168361 ÷ 100000).
Open a pair for the converter, the table, and the worked examples. The unit converter collects every unit in the factor table, including the ones that are only there so a pair can warn you about them.
Frequently asked questions
Are these the same numbers as the unit converter?
Yes. Both call one factor table. A result that differs is a bug, not a second definition.
Which gallon is the gallon page?
The US liquid gallon, 3.785411784 litres. The imperial gallon is 4.54609 litres and is described on that page so it is not silent.
Do MB and MiB share a page?
No. The MB pages use decimal 1000. The unit converter lists MiB and GiB beside them.
Does the temperature page convert a difference?
The box converts a reading, offset included. The pitfalls explain how to scale a difference without adding 32 or subtracting 273.15.