Unit converter — convert measurements instantly

Choose a category, enter a value, and select the units. The result appears immediately with the formula, conversion table, and reference source.

Verified August 23, 2026Published by ConverterBaseSources NIST and BIPM

Currency cm to inches cm to feet and inches meters to feet and inches mm to feet and inches mm to fractional inches

Quick converter

Value to convert Type From To

3.937 in1 cm = 0.3937 in

Precision

474: focused tools
23: measurement categories
33: localized editions

Fixed conversions run locally in your browser. Values are not uploaded.

Popular conversions

Direct routes for common measurements and multi-part values.

CurrencyConvert world currencies with the latest available exchange rates, a visible rate date, and no account or API key required.cm to inchesFor product dimensions, rulers, and screen specs. Exact: 1 in = 2.54 cm.cm to feet and inchesBest for human height, forms, sports profiles, and passport-style measurements.meters to feet and inchesFor height, room dimensions, product specs, and plans that need feet plus inches.mm to feet and inchesFor plans, product dimensions, and height measurements written in millimeters.mm to fractional inchesFor drill bits, fasteners, workshop measurements, and specs that use inch fractions.fractional inches to mmFor drill bits, fasteners, workshop measurements, and inch-fraction specs.kg to lbsFor body weight, luggage, gym plates, and shipping labels.kg to stone and poundsFor UK and Ireland body weight: kilograms to stone plus pounds.Celsius to FahrenheitFor weather, ovens, thermostats, and travel temperatures.Recipe VolumeFor recipe scaling, U.S. cups, milliliters, tablespoons, teaspoons, and fluid ounces.mm to inchesFor small parts, drill bits, fasteners, and specs.

Browse unit categories

Metric, imperial, U.S. customary, scientific, electrical, and digital units.

Length66 converterscm to inches, inches to cm, mm to inches Temperature6 convertersCelsius to Fahrenheit, Fahrenheit to Celsius, Celsius to Kelvin Weight42 converterskg to lbs, lbs to kg, kg to grams Volume69 convertersliters to gallons, gallons to liters, liters to mL Area34 convertersacres to square feet, square feet to acres, square feet to m² Speed16 convertersmph to kph, kph to mph, mph to m/s Time24 convertershours to minutes, minutes to hours, seconds to minutes Digital35 convertersMB to GB, GB to MB, KB to MB Data rate18 convertersMbps to Kbps, Kbps to Mbps, Mbps to Gbps Angle12 convertersradians to degrees, degrees to radians, degrees to turns Pressure23 converterspsi to bar, bar to psi, psi to kPa Power16 convertershp to kW, kW to hp, watts to kW Force10 convertersnewtons to lbf, lbf to newtons, kilonewtons to lbf Torque12 convertersnewton meters to lb ft, lb ft to newton meters, newton meters to lb in Frequency12 convertersrpm to Hz, Hz to rpm, kHz to Hz Energy14 convertersjoules to kJ, kJ to joules, kWh to joules Acceleration10 convertersm/s² to g-force, g-force to m/s², ft/s² to m/s² Flow rate12 convertersL/min to gpm, gpm to L/min, L/s to L/min Density10 converterskg/m³ to g/cm³, g/cm³ to kg/m³, g/mL to kg/m³ Electric current8 convertersamps to mA, mA to amps, amps to µA Voltage8 convertersvolts to mV, mV to volts, kV to volts Resistance8 convertersohms to kΩ, kΩ to ohms, MΩ to ohms Illuminance8 converterslux to foot-candles, foot-candles to lux, kilolux to lux

How does the unit converter work?

Every result is calculated from the same structured unit record used by the page formula and table. One inch, for example, is defined as exactly 2.54 centimeters.

Check the NIST conversion factors or read the ConverterBase methodology.

Definition: Stable factors from NIST and BIPM
Calculation: Full internal precision, rounded only for display
Ambiguity: U.S. and imperial gallons, bits and bytes, power and energy are kept distinct

Choose by task

Start from the job when you do not know the unit category.

Money & travel1 converters

Measurements17 converters

Weight10 converters

Cooking & liquid9 converters

Travel & speed7 converters

Data & downloads15 converters

Engineering12 converters

Energy & electrical8 converters

More converters by category

Open a category for a short selection, then continue to its complete converter list.

Length66 converters

cm to inches1 cm = 0.3937 in inches to cm1 in = 2.54 cm mm to inches1 mm = 0.03937 in inches to mm1 in = 25.4 mm Browse all 66 length converters

Temperature6 converters

Celsius to Fahrenheit1 °C = 33.8 °F Fahrenheit to Celsius1 °F = -17.2222 °C Celsius to Kelvin1 °C = 274.15 K Kelvin to Celsius1 K = -272.15 °C Browse all 6 temperature converters

Weight42 converters

kg to lbs1 kg = 2.2046 lb lbs to kg1 lb = 0.45359 kg kg to grams1 kg = 1,000 g grams to kg1 g = 0.001 kg Browse all 42 weight converters

Volume69 converters

liters to gallons1 L = 0.26417 gal gallons to liters1 gal = 3.7854 L liters to mL1 L = 1,000 mL mL to liters1 mL = 0.001 L Browse all 69 volume converters

Area34 converters

acres to square feet1 acre = 43,560 ft² square feet to acres1 ft² = 2.29568e-5 acre square feet to m²1 ft² = 0.0929 m² m² to square feet1 m² = 10.7639 ft² Browse all 34 area converters

Speed16 converters

mph to kph1 mph = 1.6093 km/h kph to mph1 km/h = 0.62137 mph mph to m/s1 mph = 0.44704 m/s m/s to kph1 m/s = 3.6 km/h Browse all 16 speed converters

Time24 converters

hours to minutes1 hr = 60 min minutes to hours1 min = 0.01667 hr seconds to minutes1 s = 0.01667 min minutes to seconds1 min = 60 s Browse all 24 time converters

Digital35 converters

MB to GB1 MB = 0.001 GB GB to MB1 GB = 1,000 MB KB to MB1 KB = 0.001 MB MB to KB1 MB = 1,000 KB Browse all 35 digital converters

Data rate18 converters

Mbps to Kbps1 Mbps = 1,000 Kbps Kbps to Mbps1 Kbps = 0.001 Mbps Mbps to Gbps1 Mbps = 0.001 Gbps Gbps to Mbps1 Gbps = 1,000 Mbps Browse all 18 data rate converters

Angle12 converters

radians to degrees1 rad = 57.2958 deg degrees to radians1 deg = 0.01745 rad degrees to turns1 deg = 0.002778 turn turns to degrees1 turn = 360 deg Browse all 12 angle converters

Pressure23 converters

psi to bar1 psi = 0.06895 bar bar to psi1 bar = 14.5038 psi psi to kPa1 psi = 6.8948 kPa kPa to psi1 kPa = 0.14504 psi Browse all 23 pressure converters

Power16 converters

hp to kW1 hp = 0.7457 kW kW to hp1 kW = 1.341 hp watts to kW1 W = 0.001 kW kW to watts1 kW = 1,000 W Browse all 16 power converters

Force10 converters

newtons to lbf1 N = 0.22481 lbf lbf to newtons1 lbf = 4.4482 N kilonewtons to lbf1 kN = 224.81 lbf lbf to kilonewtons1 lbf = 0.004448 kN Browse all 10 force converters

Torque12 converters

newton meters to lb ft1 N m = 0.73756 lb ft lb ft to newton meters1 lb ft = 1.3558 N m newton meters to lb in1 N m = 8.8507 lb in lb in to newton meters1 lb in = 0.11298 N m Browse all 12 torque converters

Frequency12 converters

rpm to Hz1 rpm = 0.01667 Hz Hz to rpm1 Hz = 60 rpm kHz to Hz1 kHz = 1,000 Hz Hz to kHz1 Hz = 0.001 kHz Browse all 12 frequency converters

Energy14 converters

joules to kJ1 J = 0.001 kJ kJ to joules1 kJ = 1,000 J kWh to joules1 kWh = 3,600,000 J joules to kWh1 J = 2.77778e-7 kWh Browse all 14 energy converters

Acceleration10 converters

m/s² to g-force1 m/s² = 0.10197 g g-force to m/s²1 g = 9.8066 m/s² ft/s² to m/s²1 ft/s² = 0.3048 m/s² m/s² to ft/s²1 m/s² = 3.2808 ft/s² Browse all 10 acceleration converters

Flow rate12 converters

L/min to gpm1 L/min = 0.26417 gpm gpm to L/min1 gpm = 3.7854 L/min L/s to L/min1 L/s = 60 L/min L/min to L/s1 L/min = 0.01667 L/s Browse all 12 flow rate converters

Density10 converters

kg/m³ to g/cm³1 kg/m³ = 0.001 g/cm³ g/cm³ to kg/m³1 g/cm³ = 1,000 kg/m³ g/mL to kg/m³1 g/mL = 1,000 kg/m³ kg/m³ to g/mL1 kg/m³ = 0.001 g/mL Browse all 10 density converters

Electric current8 converters

amps to mA1 A = 1,000 mA mA to amps1 mA = 0.001 A amps to µA1 A = 1,000,000 µA µA to amps1 µA = 1e-6 A Browse all 8 electric current converters

Voltage8 converters

volts to mV1 V = 1,000 mV mV to volts1 mV = 0.001 V kV to volts1 kV = 1,000 V volts to kV1 V = 0.001 kV Browse all 8 voltage converters

Resistance8 converters

ohms to kΩ1 Ω = 0.001 kΩ kΩ to ohms1 kΩ = 1,000 Ω MΩ to ohms1 MΩ = 1,000,000 Ω ohms to MΩ1 Ω = 1e-6 MΩ Browse all 8 resistance converters

Illuminance8 converters

lux to foot-candles1 lx = 0.0929 fc foot-candles to lux1 fc = 10.7639 lx kilolux to lux1 klx = 1,000 lx lux to kilolux1 lx = 0.001 klx Browse all 8 illuminance converters

ConverterBase in your language

33 localized editions with matching calculator routes and locale-aware number formatting.

EspañolConvertidor de unidades DeutschEinheitenumrechner FrançaisConvertisseur d’unités PortuguêsConversor de unidades ItalianoConvertitore di unità NederlandsEenhedenconverter PolskiPrzelicznik jednostek SvenskaEnhetsomvandlare Norsk bokmålEnhetsomregner DanskEnhedsomregner SuomiYksikkömuunnin TürkçeBirim dönüştürücü 日本語単位変換 한국어단위 변환기 简体中文单位换算器 हिन्दीइकाई परिवर्तक Bahasa IndonesiaKonverter satuan Tiếng ViệtTrình chuyển đổi đơn vị ไทยเครื่องมือแปลงหน่วย ČeštinaPřevodník jednotek RomânăConvertor de unități MagyarMértékegység-átváltó ΕλληνικάΜετατροπέας μονάδων УкраїнськаКонвертер одиниць العربيةمحول الوحدات 繁體中文單位換算器 РусскийКонвертер единиц বাংলাএকক রূপান্তরকারী اردواکائی تبدیل کرنے کا آلہ فارسیمبدل واحد Bahasa MelayuPenukar unit FilipinoConverter ng unit KiswahiliKibadilisha vipimo

Common unit-conversion questions

Short answers to the choices that most often change the result.

How do I convert units?

Choose a category, enter a value, then select the source and target units. ConverterBase updates the result immediately and shows the formula, table, and reference used for that conversion.

Are the conversion results exact?

Some relationships are exact definitions, while others are conventional or approximate factors. Each converter identifies its source and keeps more internal precision than it displays.

What is the difference between U.S. and imperial units?

Units with the same name can represent different quantities. A U.S. liquid gallon and an imperial gallon are different, so ConverterBase labels the system explicitly where ambiguity matters.

Why is converting square or cubic units different?

Area and volume include a squared or cubed length factor. Converting meters to centimeters uses 100, while square meters to square centimeters uses 100 squared, or 10,000.

Does ConverterBase upload the values I enter?

No. Fixed unit conversions run in the browser. The separate currency tool requests selected currency codes from its rate provider but does not send the amount entered.

Which sources does ConverterBase use?

Fixed unit pages cite NIST or BIPM definitions and conventional factors. The methodology page explains how shared data, formulas, charts, and automated checks are kept consistent.