Convert units

How the converter works

Pick a category, enter the value and choose the source and target unit. The result appears immediately. The swap button exchanges both units; the convert button exists for pure keyboard use. All calculation happens in your browser only.

The factors are values fixed by law or by standard. One inch is exactly 0.0254 metres, one pound exactly 0.45359237 kilograms. Up to twelve significant digits are shown; the precision selector shortens the display.

All categories and units

The overview below lists every unit with its symbol and reference value. “Reference” means: one value of this unit equals that many units of the respective base unit.

Length9

Distances and dimensions from millimetres to nautical miles.

Unit	Symbol	1 unit equals
Millimetre	mm	0.001 m
Centimetre	cm	0.01 m
Metre	m	1 m
Kilometre	km	1,000 m
Inch	in	0.0254 m
Foot	ft	0.3048 m
Yard	yd	0.9144 m
Mile	mi	1,609.344 m
Nautical mile	nmi	1,852 m

Area10

Areas from square millimetres to square miles, including hectares and acres.

Unit	Symbol	1 unit equals
Square millimetre	mm²	0.000001 m2
Square centimetre	cm²	0.0001 m2
Square metre	m²	1 m2
Square kilometre	km²	1,000,000 m2
Hectare	ha	10,000 m2
Acre	ac	4,046.8564224 m2
Square inch	in²	0.00064516 m2
Square foot	ft²	0.09290304 m2
Square yard	yd²	0.83612736 m2
Square mile	mi²	2,589,988.11034 m2

Volume17

Volumes from millilitres to cubic metres. US, imperial and dry measures are kept apart.

Unit	Symbol	1 unit equals
Millilitre	ml	0.001 l
Centilitre	cl	0.01 l
Decilitre	dl	0.1 l
Litre	l	1 l
Cubic centimetre	cm³	0.001 l
Cubic metre	m³	1,000 l
US liquid gallon	US gal	3.785411784 l
US dry gallon	US dry gal	4.40488377086 l
Imperial gallon	imp gal	4.54609 l
US fluid ounce	US fl oz	0.029573529563 l
Imperial fluid ounce	imp fl oz	0.0284130625 l
US pint	US pt	0.473176473 l
Imperial pint	imp pt	0.56826125 l
US quart	US qt	0.946352946 l
Imperial quart	imp qt	1.1365225 l
Cubic inch	in³	0.016387064 l
Cubic foot	ft³	28.316846592 l

Mass9

Units of mass from milligram to tonne. Everyday language calls it weight; technically this is mass.

Unit	Symbol	1 unit equals
Milligram	mg	0.000001 kg
Gram	g	0.001 kg
Kilogram	kg	1 kg
Metric tonne	t	1,000 kg
Ounce	oz	0.028349523125 kg
Pound	lb	0.45359237 kg
Stone	st	6.35029318 kg
US short ton	short ton	907.18474 kg
Imperial long ton	long ton	1,016.0469088 kg

Temperature3

Temperature uses offset formulas, not a factor. Absolute zero is checked.

Unit	Symbol	1 unit equals
Celsius	°C	K − 273.15 = °C
Fahrenheit	°F	(°F − 32) × 5/9 = °C
Kelvin	K	K − 273.15 = °C

Speed5

Speeds including knots for shipping and aviation.

Unit	Symbol	1 unit equals
Metre per second	m/s	1 m/s
Kilometre per hour	km/h	0.277777777778 m/s
Miles per hour	mph	0.44704 m/s
Knot	kn	0.514444444444 m/s
Feet per second	ft/s	0.3048 m/s

Time6

Durations from milliseconds to weeks. Months and years are omitted on purpose because their length depends on the calendar.

Unit	Symbol	1 unit equals
Millisecond	ms	0.001 s
Second	s	1 s
Minute	min	60 s
Hour	h	3,600 s
Day	d	86,400 s
Week	wk	604,800 s

Data volume14

Decimal units (kB, MB, GB) use 1,000; binary units (KiB, MiB, GiB) use 1,024. The two groups are not interchangeable.

Unit	Symbol	1 unit equals
Bit	bit	1 bit
Byte	B	8 bit
Kilobit (1,000 bit)	kbit	1,000 bit
Kilobyte (1,000 B)	kB	8,000 bit
Megabit	Mbit	1,000,000 bit
Megabyte (1,000,000 B)	MB	8,000,000 bit
Gigabit	Gbit	1,000,000,000 bit
Gigabyte (1,000,000,000 B)	GB	8,000,000,000 bit
Terabit	Tbit	1,000,000,000,000 bit
Terabyte (1,000,000,000,000 B)	TB	8,000,000,000,000 bit
Kibibyte (1,024 B)	KiB	8,192 bit
Mebibyte (1,024 KiB)	MiB	8,388,608 bit
Gibibyte (1,024 MiB)	GiB	8,589,934,592 bit
Tebibyte (1,024 GiB)	TiB	8,796,093,022,208 bit

Pressure10

Pressure from pascal to psi, including bar, atmosphere and millimetres of mercury.

Unit	Symbol	1 unit equals
Pascal	Pa	1 Pa
Kilopascal	kPa	1,000 Pa
Megapascal	MPa	1,000,000 Pa
Bar	bar	100,000 Pa
Millibar	mbar	100 Pa
Hectopascal	hPa	100 Pa
Standard atmosphere	atm	101,325 Pa
Torr	Torr	133.322368421 Pa
Millimetre of mercury	mmHg	133.322387415 Pa
Pound per square inch	psi	6,894.75729317 Pa

Energy10

Energy from joule to kilowatt hour. Calorie and kilocalorie differ; food labels usually use kilocalories.

Unit	Symbol	1 unit equals
Joule	J	1 J
Kilojoule	kJ	1,000 J
Megajoule	MJ	1,000,000 J
Watt hour	Wh	3,600 J
Kilowatt hour	kWh	3,600,000 J
Megawatt hour	MWh	3,600,000,000 J
Calorie	cal	4.184 J
Kilocalorie	kcal	4,184 J
British thermal unit (IT)	BTU	1,055.05585262 J
Electronvolt	eV	1.602177e-19 J

Power5

Power from watt to megawatt. Metric horsepower (PS) and mechanical horsepower (hp) differ.

Unit	Symbol	1 unit equals
Watt	W	1 W
Kilowatt	kW	1,000 W
Megawatt	MW	1,000,000 W
Metric horsepower	PS	735.49875 W
Mechanical horsepower	hp	745.699871582 W

Fuel consumption4

Consumption is a reciprocal: litres per 100 kilometres face distance per litre, so the conversion divides instead of multiplying.

Unit	Symbol	1 unit equals
Litres per 100 kilometres	l/100 km	—
Kilometres per litre	km/l	km/l = 100 ÷ (l/100 km)
US miles per gallon	mpg US	mpg US = 235.214583 ÷ (l/100 km)
Imperial miles per gallon	mpg imp	mpg imp = 282.480936 ÷ (l/100 km)

Angle7

Plane angles from degrees via radians to gon.

Unit	Symbol	1 unit equals
Radian	rad	1 rad
Degree	°	0.01745329252 rad
Gon	gon	0.015707963268 rad
Turn	turn	6.28318530718 rad
Arcminute	′	0.000290888209 rad
Arcsecond	″	0.000004848137 rad
Milliradian	mrad	0.001 rad

Frequency6

Frequency in hertz plus rotational speeds per minute.

Unit	Symbol	1 unit equals
Hertz	Hz	1 Hz
Kilohertz	kHz	1,000 Hz
Megahertz	MHz	1,000,000 Hz
Gigahertz	GHz	1,000,000,000 Hz
Terahertz	THz	1,000,000,000,000 Hz
Revolutions per minute	1/min	0.016666666667 Hz

Torque5

Torque from newton metres to pound-feet.

Unit	Symbol	1 unit equals
Newton metre	N·m	1 N·m
Kilonewton metre	kN·m	1,000 N·m
Metre-kilopond	m·kgf	9.80665 N·m
Pound-foot	lbf·ft	1.35581794833 N·m
Pound-inch	lbf·in	0.112984829028 N·m

Force6

Forces from newton to dyne.

Unit	Symbol	1 unit equals
Newton	N	1 N
Kilonewton	kN	1,000 N
Millinewton	mN	0.001 N
Kilopond	kgf	9.80665 N
Pound-force	lbf	4.44822161526 N
Dyne	dyn	0.00001 N

Density6

Density is mass per volume. It is the factor linking the mass and the volume of a substance.

Unit	Symbol	1 unit equals
Kilogram per cubic metre	kg/m³	1 kg/m³
Gram per cubic centimetre	g/cm³	1,000 kg/m³
Gram per litre	g/l	1 kg/m³
Kilogram per litre	kg/l	1,000 kg/m³
Pound per cubic foot	lb/ft³	16.018463374 kg/m³
Pound per cubic inch	lb/in³	27,679.9047102 kg/m³

Flow rate9

Volume flow per time, for example for pumps, pipes and ventilation.

Unit	Symbol	1 unit equals
Cubic metre per second	m³/s	1 m³/s
Cubic metre per hour	m³/h	0.000277777778 m³/s
Litre per second	l/s	0.001 m³/s
Litre per minute	l/min	0.000016666667 m³/s
Litre per hour	l/h	0.000000277778 m³/s
US gallons per minute	US gal/min	0.000063090196 m³/s
Imperial gallons per minute	imp gal/min	0.000075768167 m³/s
Cubic feet per minute	ft³/min	0.000471947443 m³/s
Cubic feet per second	ft³/s	0.028316846592 m³/s

Acceleration4

Acceleration including the standard acceleration of free fall g.

Unit	Symbol	1 unit equals
Metre per second squared	m/s²	1 m/s²
Foot per second squared	ft/s²	0.3048 m/s²
Standard gravity	g	9.80665 m/s²
Gal	Gal	0.01 m/s²

Angular velocity5

Angle per time, for example for motors and turntables.

Unit	Symbol	1 unit equals
Radians per second	rad/s	1 rad/s
Degrees per second	°/s	0.01745329252 rad/s
Degrees per minute	°/min	0.000290888209 rad/s
Radians per minute	rad/min	0.016666666667 rad/s
Revolutions per minute	1/min	0.10471975512 rad/s

Solid angle3

Solid angle in steradians and square degrees.

Unit	Symbol	1 unit equals
Steradian	sr	1 sr
Millisteradian	msr	0.001 sr
Square degree	deg²	0.00030461742 sr

Specific weight4

Specific weight is weight force per volume – not to be confused with density, which is mass per volume.

Unit	Symbol	1 unit equals
Newton per cubic metre	N/m³	1 N/m³
Kilonewton per cubic metre	kN/m³	1,000 N/m³
Kilopond per cubic metre	kgf/m³	9.80665 N/m³
Pound-force per cubic foot	lbf/ft³	157.087463844 N/m³

Dynamic viscosity6

Dynamic viscosity describes a fluid’s resistance to flow. It cannot be converted into kinematic viscosity without a known density, hence a separate category.

Unit	Symbol	1 unit equals
Pascal second	Pa·s	1 Pa·s
Millipascal second	mPa·s	0.001 Pa·s
Centipoise	cP	0.001 Pa·s
Poise	P	0.1 Pa·s
Pound-force second per square foot	lbf·s/ft²	47.8802589803 Pa·s
Kilopond second per square metre	kgf·s/m²	9.80665 Pa·s

Kinematic viscosity5

Kinematic viscosity is dynamic viscosity divided by density. A separate category, because deriving it from dynamic viscosity would require a density.

Unit	Symbol	1 unit equals
Square metre per second	m²/s	1 m²/s
Square millimetre per second	mm²/s	0.000001 m²/s
Centistokes	cSt	0.000001 m²/s
Stokes	St	0.0001 m²/s
Square foot per second	ft²/s	0.09290304 m²/s

Electric current4

Current in amperes.

Unit	Symbol	1 unit equals
Ampere	A	1 A
Milliampere	mA	0.001 A
Microampere	µA	0.000001 A
Kiloampere	kA	1,000 A

Voltage5

Voltage in volts.

Unit	Symbol	1 unit equals
Volt	V	1 V
Millivolt	mV	0.001 V
Microvolt	µV	0.000001 V
Kilovolt	kV	1,000 V
Megavolt	MV	1,000,000 V

Electrical resistance5

Resistance in ohms. Conductance is its reciprocal and has its own category.

Unit	Symbol	1 unit equals
Ohm	Ω	1 Ω
Milliohm	mΩ	0.001 Ω
Kiloohm	kΩ	1,000 Ω
Megaohm	MΩ	1,000,000 Ω
Gigaohm	GΩ	1,000,000,000 Ω

Electrical conductance4

Conductance in siemens. It is the reciprocal of resistance and a different quantity from conductivity in siemens per metre.

Unit	Symbol	1 unit equals
Siemens	S	1 S
Millisiemens	mS	0.001 S
Microsiemens	µS	0.000001 S
Kilosiemens	kS	1,000 S

Electrical conductivity5

Conductivity in siemens per metre, common in water analysis. Not to be confused with conductance in siemens.

Unit	Symbol	1 unit equals
Siemens per metre	S/m	1 S/m
Millisiemens per metre	mS/m	0.001 S/m
Millisiemens per centimetre	mS/cm	0.1 S/m
Microsiemens per centimetre	µS/cm	0.0001 S/m
Siemens per centimetre	S/cm	100 S/m

Electric charge6

Charge in coulombs and in ampere hours as printed on batteries.

Unit	Symbol	1 unit equals
Coulomb	C	1 C
Millicoulomb	mC	0.001 C
Microcoulomb	µC	0.000001 C
Kilocoulomb	kC	1,000 C
Ampere hour	Ah	3,600 C
Milliampere hour	mAh	3.6 C

Capacitance5

Capacitance in farads, from microfarad to picofarad.

Unit	Symbol	1 unit equals
Farad	F	1 F
Millifarad	mF	0.001 F
Microfarad	µF	0.000001 F
Nanofarad	nF	0.000000001 F
Picofarad	pF	1.000000e-12 F

Inductance4

Inductance in henries.

Unit	Symbol	1 unit equals
Henry	H	1 H
Millihenry	mH	0.001 H
Microhenry	µH	0.000001 H
Nanohenry	nH	0.000000001 H

Magnetic flux4

Magnetic flux in webers and maxwells.

Unit	Symbol	1 unit equals
Weber	Wb	1 Wb
Milliweber	mWb	0.001 Wb
Microweber	µWb	0.000001 Wb
Maxwell	Mx	0.00000001 Wb

Magnetic flux density5

Flux density in tesla and gauss. Tesla is the SI unit; gauss is still used in engineering.

Unit	Symbol	1 unit equals
Tesla	T	1 T
Millitesla	mT	0.001 T
Microtesla	µT	0.000001 T
Nanotesla	nT	0.000000001 T
Gauss	G	0.0001 T

Magnetic field strength3

Magnetic field strength H in amperes per metre and in oersteds. It is a different quantity from magnetic flux density B and a different one from magnetization M.

Unit	Symbol	1 unit equals
Ampere per metre	A/m	1 A/m
Kiloampere per metre	kA/m	1,000 A/m
Oersted	Oe	79.5774715459 A/m

Magnetization3

Magnetization M in amperes per metre. M and magnetic field strength H are different quantities even though both are quoted in amperes per metre: H describes the applied field, M the magnetic alignment of the material. Oersted belongs to field strength, not here.

Unit	Symbol	1 unit equals
Ampere per metre	A/m	1 A/m
Kiloampere per metre	kA/m	1,000 A/m
Megaampere per metre	MA/m	1,000,000 A/m

Radioactivity (activity)7

Decays per second. Activity, absorbed dose and equivalent dose are three different quantities in three separate categories.

Unit	Symbol	1 unit equals
Becquerel	Bq	1 Bq
Kilobecquerel	kBq	1,000 Bq
Megabecquerel	MBq	1,000,000 Bq
Gigabecquerel	GBq	1,000,000,000 Bq
Curie	Ci	37,000,000,000 Bq
Millicurie	mCi	37,000,000 Bq
Microcurie	µCi	37,000 Bq

Absorbed radiation dose5

Energy absorbed per kilogram of material. Not to be confused with activity or equivalent dose.

Unit	Symbol	1 unit equals
Gray	Gy	1 Gy
Milligray	mGy	0.001 Gy
Microgray	µGy	0.000001 Gy
Rad	rad	0.01 Gy
Kilorad	krad	10 Gy

Equivalent dose5

Radiation dose weighted for biological effect. A separate category next to absorbed dose.

Unit	Symbol	1 unit equals
Sievert	Sv	1 Sv
Millisievert	mSv	0.001 Sv
Microsievert	µSv	0.000001 Sv
Rem	rem	0.01 Sv
Millirem	mrem	0.00001 Sv

Luminous intensity3

Luminous intensity in candela. Intensity, flux, illuminance and luminance are four different quantities and cannot be converted into one another directly.

Unit	Symbol	1 unit equals
Candela	cd	1 cd
Millicandela	mcd	0.001 cd
Kilocandela	kcd	1,000 cd

Luminance6

Luminance describes how bright a surface appears. It is neither luminous intensity nor luminous flux.

Unit	Symbol	1 unit equals
Candela per square metre	cd/m²	1 cd/m²
Nit	nt	1 cd/m²
Candela per square centimetre	cd/cm²	10,000 cd/m²
Stilb	sb	10,000 cd/m²
Foot-lambert	fL	3.42625909964 cd/m²
Lambert	L	3,183.09886184 cd/m²

Luminous flux3

Luminous flux in lumens, the figure printed on lamp packaging.

Unit	Symbol	1 unit equals
Lumen	lm	1 lm
Kilolumen	klm	1,000 lm
Millilumen	mlm	0.001 lm

Illuminance4

Illuminance in lux, that is luminous flux per area. It says nothing about the brightness of the emitting surface itself.

Unit	Symbol	1 unit equals
Lux	lx	1 lx
Kilolux	klx	1,000 lx
Millilux	mlx	0.001 lx
Foot-candle	fc	10.7639104167 lx

Quantity of light3

Luminous flux over a period, for example for flash or exposure planning.

Unit	Symbol	1 unit equals
Lumen second	lm·s	1 lm·s
Lumen hour	lm·h	3,600 lm·s
Talbot	talbot	1 lm·s

Luminous exposure2

Illuminance over a period, the quantity behind exposure time in photography.

Unit	Symbol	1 unit equals
Lux second	lx·s	1 lx·s
Lux hour	lx·h	3,600 lx·s

Data transfer rate12

Transfer speed, not to be confused with data volume. Decimal prefixes use 1,000, binary prefixes 1,024.

Unit	Symbol	1 unit equals
Bits per second	bit/s	1 bit/s
Kilobits per second	kbit/s	1,000 bit/s
Megabits per second	Mbit/s	1,000,000 bit/s
Gigabits per second	Gbit/s	1,000,000,000 bit/s
Terabits per second	Tbit/s	1,000,000,000,000 bit/s
Bytes per second	B/s	8 bit/s
Kilobytes per second	kB/s	8,000 bit/s
Megabytes per second	MB/s	8,000,000 bit/s
Gigabytes per second	GB/s	8,000,000,000 bit/s
Kibibytes per second	KiB/s	8,192 bit/s
Mebibytes per second	MiB/s	8,388,608 bit/s
Gibibytes per second	GiB/s	8,589,934,592 bit/s

Telling US, imperial and metric measures apart

Units with the same name are not the same size. A US liquid gallon holds 3.785411784 litres, a British imperial gallon 4.54609 litres and a US dry gallon 4.40488377086 litres. For volume we therefore list every variant separately and always spell out its origin. The same applies to the fluid ounce, pint and quart as well as to the short ton and the long ton. For fuel consumption, US and imperial mpg differ.

Decimal and binary data volumes

Drive makers calculate in decimal: one kilobyte is 1,000 bytes, one gigabyte 1,000,000,000 bytes. Operating systems often show binary: one kibibyte is 1,024 bytes, one gibibyte 1,024 mebibytes. That is why a purchased drive looks smaller than advertised. This converter keeps the two groups apart and never equates megabyte with mebibyte.

Temperature and fuel consumption

Temperature cannot be converted with a factor because the scales are offset. We convert via Celsius: kelvin is Celsius plus 273.15, Fahrenheit is Celsius times 9/5 plus 32. Values below absolute zero are rejected. Fuel consumption is a reciprocal: litres per 100 kilometres face distance per litre, so the conversion divides instead of multiplying.

Example: gallons to litres

One US liquid gallon equals 3.785411784 litres. One litre is the reciprocal, about 0.2641720524 US liquid gallons. Fifteen US liquid gallons come to about 56.78117676 litres.

Frequently asked questions

How many litres are in a gallon?

A US liquid gallon holds 3.785411784 litres, a British imperial gallon 4.54609 litres and a US dry gallon 4.40488377086 litres. The three measures differ and are listed separately here.

How do I convert miles to kilometres?

One mile is exactly 1,609.344 metres, so 1.609344 kilometres. Multiply the number of miles by 1.609344, or simply enter the value in this converter.

How does the converter turn Fahrenheit into Celsius?

With the formula °C = (°F − 32) × 5/9. Freezing point is 32 °F, which is 0 °C; boiling point is 212 °F, which is 100 °C.

What is the difference between MB and MiB?

MB is decimal and stands for 1,000,000 bytes; MiB is binary and stands for 1,048,576 bytes. One gigabyte is roughly 0.9313 gibibytes.

Are my entries stored?

No. The converter runs entirely in your browser; there is no external interface, no storage and no transmission of values.

Sources and method

Every factor is checked against recognised standards and institutional sources: the BIPM SI system, the conversion factors of the United States National Institute of Standards and Technology (NIST SP 811 Appendix B.8 and NIST Handbook 44 Appendix C), the British Weights and Measures Act 1985 for imperial volumes, the ISO 80000 series for heat and power and IEC 80000-13 for binary data volumes.

Currency conversion is deliberately absent; a separate calculator with variable rates exists for that. Mass and volume cannot be converted into each other without a known density, so kitchen conversions from grams to millilitres are omitted. Months and years are missing from the time units because their length depends on the calendar.

Common conversions