Direct conversions

UnitCloud is a local measurement lab for everyday work, engineering, IT, energy, mobility and design. Every conversion shows result, formula, base unit, rounding and the common mistake.

Convert

Common direct conversions

Inch to Centimetrein → cmLength Centimetre to Inchcm → inLength Foot to Metreft → mLength Metre to Footm → ftLength Mile to Kilometremi → kmLength Kilometre to Milekm → miLength Nautical mile to Kilometrenmi → kmLength Hectare to Square metreha → m²Area Square metre to Hectarem² → haArea Acre to Square metreacre → m²Area Litre to US gallonl → galVolume US gallon to Litregal → lVolume Millilitre to Cupml → cupVolume Cup to Millilitrecup → mlVolume Pound to Kilogramlb → kgMass Kilogram to Poundkg → lbMass

Length

Inch, foot and mile use fixed factors. Errors usually come from early rounding or from mixing land miles and nautical miles.

Table

Base unitm

All target values7

SourcesBIPM SI Brochure · NIST Guide to SI Appendix B

Area

Area scales quadratically. A length factor is not automatically an area factor.

Table

Base unitm²

All target values3

SourcesBIPM SI Brochure · NIST Guide to SI Appendix B

Hectare to Square metreha → m²Area Square metre to Hectarem² → haArea Acre to Square metreacre → m²Area

Volume

Volume is robust for liquids. For dry ingredients it does not replace weighing because density and packing vary.

Table

Base unitl

All target values4

SourcesBIPM SI Brochure · NIST Guide to SI Appendix B

Litre to US gallonl → galVolume US gallon to Litregal → lVolume Millilitre to Cupml → cupVolume Cup to Millilitrecup → mlVolume

Mass

Pound is not always the same local unit. UnitCloud uses international avoirdupois values.

Table

Base unitg

All target values4

SourcesBIPM SI Brochure · NIST Guide to SI Appendix B

Pound to Kilogramlb → kgMass Kilogram to Poundkg → lbMass Ounce to Gramoz → gMass Gram to Ounceg → ozMass

Temperature

Temperature uses an offset. Fahrenheit and Kelvin are not pure factor units.

Table

Base unit°C

All target values4

SourcesBIPM SI Brochure · NIST Metric SI · NIST Guide to SI Appendix B

Fahrenheit to Celsius°F → °CTemperature Celsius to Fahrenheit°C → °FTemperature Kelvin to CelsiusK → °CTemperature Celsius to Kelvin°C → KTemperature

Data

KB, MB and GB are decimal. KiB, MiB and GiB are binary. This distinction explains many apparent storage gaps.

Table

Base unitByte

All target values6

SourcesNIST Metric SI Prefixes · NIST Binary Prefixes

Gigabyte to GibibyteGB → GiBData Gibibyte to GigabyteGiB → GBData Mebibyte to MegabyteMiB → MBData Megabyte to MebibyteMB → MiBData Bit to Bytebit → BData Terabyte to TebibyteTB → TiBData

Speed

Knots are nautical miles per hour. mph and knots are not interchangeable imperial speeds.

Table

Base unitm/s

All target values5

SourcesBIPM SI Brochure · NIST Guide to SI Appendix B

Knot to Kilometres per hourkn → km/hSpeed Kilometres per hour to Knotkm/h → knSpeed Miles per hour to Kilometres per hourmph → km/hSpeed Kilometres per hour to Miles per hourkm/h → mphSpeed Metres per second to Kilometres per hourm/s → km/hSpeed

Energy

Food calories are kilocalories. Utility bills use kilowatt-hours. Both are energy units, but in different contexts.

Table

Base unitJ

All target values5

SourcesBIPM SI Brochure · NIST Guide to SI Appendix B

Kilowatt-hour to JoulekWh → JEnergy Joule to Kilowatt-hourJ → kWhEnergy Kilocalorie to Kilojoulekcal → kJEnergy Kilojoule to KilocaloriekJ → kcalEnergy British thermal unit to Kilowatt-hourBTU → kWhEnergy

Power

PS and hp are not identical. Vehicle data often uses metric horsepower, while US/UK contexts often use mechanical horsepower.

Table

Base unitW

All target values4

SourcesBIPM SI Brochure · NIST Guide to SI Appendix B

Kilowatt to Metric horsepowerkW → PSPower Metric horsepower to KilowattPS → kWPower Kilowatt to Mechanical horsepowerkW → hpPower Watt to BTU per hourW → BTU/hPower

Pressure

bar, psi and atm appear in different fields. Tyre, weather and lab values need context.

Table

Base unitPa

All target values4

SourcesBIPM SI Brochure · NIST Guide to SI Appendix B.8

bar to psibar → psiPressure psi to barpsi → barPressure Kilopascal to psikPa → psiPressure Atmosphere to baratm → barPressure

Density

Density depends on temperature, material state and measurement conditions. Unit conversion does not replace material data.

Table

Base unitkg/m³

All target values2

SourcesBIPM SI Brochure · NIST Guide to SI Appendix B

Gram per cubic centimetre to Kilogram per cubic metreg/cm³ → kg/m³Density Kilogram per cubic metre to Gram per cubic centimetrekg/m³ → g/cm³Density

Time

Calendar months and years vary. This family uses fixed seconds for technical durations, not legal deadlines.

Table

Base units

All target values3

SourcesBIPM SI Brochure · NIST Metric SI

Hour to Secondh → sTime Day to Hourd → hTime Week to Dayweek → dTime

Angle

Degrees and radians are often mixed in software, geometry and trigonometry. Formulas usually expect a specific angle unit.

Table

Base unitrad

All target values2

SourcesBIPM SI Brochure · NIST Guide to SI Appendix B

Degree to Radian° → radAngle Radian to Degreerad → °Angle

Force

Force and mass are not the same. Kilogram is mass, newton is force.

Table

Base unitN

All target values2

SourcesBIPM SI Brochure · NIST Guide to SI Appendix B.8

Newton to Pound-forceN → lbfForce Pound-force to Newtonlbf → NForce

Torque

Torque is not power. Newton metre and hp/kW answer different questions.

Table

Base unitN·m

All target values2

SourcesBIPM SI Brochure · NIST Guide to SI Appendix B

Newton metre to Pound-footN·m → lb·ftTorque Pound-foot to Newton metrelb·ft → N·mTorque

Fuel economy

mpg and l/100 km move in opposite directions. Higher mpg means lower consumption; higher l/100 km means higher consumption.

Table

Base unitl/100 km

All target values3

SourcesNIST Guide to SI Appendix B

Miles per US gallon to Litres per 100 kilometresmpg US → l/100 kmFuel economy Litres per 100 kilometres to Miles per US gallonl/100 km → mpg USFuel economy Kilometres per litre to Litres per 100 kilometreskm/l → l/100 kmFuel economy

Typography

px depends on output context. UnitCloud uses the CSS reference of 96 px per inch.

Table

Base unitpt

All target values3

SourcesNIST Guide to SI Appendix B · W3C CSS Values and Units

Point to CSS pixelpt → pxTypography CSS pixel to Pointpx → ptTypography Millimetre to Pointmm → ptTypography

Image resolution

Pixel count and print density are different. Print sizes also need width, height and ppi.

Table

Base unitpx

All target values2

SourcesNIST Metric SI Prefixes

Megapixel to PixelMP → pxImage resolution Pixel to Megapixelpx → MPImage resolution

Frequency

rpm and bpm are events per minute. Hz is events per second.

Table

Base unitHz

All target values3

SourcesBIPM SI Brochure · NIST Metric SI

Hertz to Revolutions per minuteHz → rpmFrequency Revolutions per minute to Hertzrpm → HzFrequency Megahertz to GigahertzMHz → GHzFrequency