Common Measurement Units and Their Conversions

Common Measurement Units and Their Conversions – Complete Reference Guide

Measurements are everywhere. From cooking and driving to building and science, we use measurement units constantly. But with so many different units and systems, it's easy to get confused.

This comprehensive reference guide covers the most common measurement units across all categories, with clear conversion formulas, quick reference tables, and practical examples.

Try it now: Use our free unit converter here

Quick Reference: Most Common Conversions

Length

Conversion	Formula	Example
Inches to cm	cm = in × 2.54	10 in = 25.4 cm
cm to inches	in = cm × 0.394	100 cm = 39.4 in
Feet to meters	m = ft × 0.305	10 ft = 3.05 m
Meters to feet	ft = m × 3.281	10 m = 32.81 ft
Miles to km	km = mi × 1.609	10 mi = 16.09 km
km to miles	mi = km × 0.621	10 km = 6.21 mi

Weight

Conversion	Formula	Example
Pounds to kg	kg = lb × 0.454	10 lb = 4.54 kg
kg to pounds	lb = kg × 2.205	10 kg = 22.05 lb
Ounces to grams	g = oz × 28.35	10 oz = 283.5 g
Grams to ounces	oz = g × 0.035	100 g = 3.53 oz

Volume

Conversion	Formula	Example
Gallons to liters	L = gal × 3.785	1 gal = 3.79 L
Liters to gallons	gal = L × 0.264	10 L = 2.64 gal
Cups to mL	mL = cup × 236.6	1 cup = 236.6 mL
mL to cups	cup = mL × 0.004	500 mL = 2.11 cups

Temperature

Conversion	Formula	Example
°C to °F	°F = (°C × 9/5) + 32	25°C = 77°F
°F to °C	°C = (°F − 32) × 5/9	77°F = 25°C
°C to K	K = °C + 273.15	25°C = 298.15 K
K to °C	°C = K − 273.15	298.15 K = 25°C

Speed

Conversion	Formula	Example
mph to km/h	km/h = mph × 1.609	60 mph = 96.6 km/h
km/h to mph	mph = km/h × 0.621	100 km/h = 62.1 mph
m/s to km/h	km/h = m/s × 3.6	10 m/s = 36 km/h
knots to km/h	km/h = kn × 1.852	10 kn = 18.52 km/h

Length Units

Imperial/US Customary

Unit	Symbol	Value in Feet	Value in Meters
Inch	in	1/12 ft	0.0254 m
Foot	ft	1 ft	0.3048 m
Yard	yd	3 ft	0.9144 m
Mile	mi	5,280 ft	1,609.34 m

Metric

Unit	Symbol	Value in Meters
Millimeter	mm	0.001 m
Centimeter	cm	0.01 m
Decimeter	dm	0.1 m
Meter	m	1 m
Kilometer	km	1,000 m

Length Conversion Table

From	To	Multiply By
Inches	Centimeters	2.54
Feet	Meters	0.3048
Yards	Meters	0.9144
Miles	Kilometers	1.60934
Centimeters	Inches	0.393701
Meters	Feet	3.28084
Meters	Yards	1.09361
Kilometers	Miles	0.621371

Weight Units

Imperial/US Customary

Unit	Symbol	Value in Ounces	Value in Kilograms
Ounce	oz	1 oz	0.02835 kg
Pound	lb	16 oz	0.45359 kg
Stone	st	224 oz	6.35029 kg
Short Ton	T	32,000 oz	907.185 kg

Metric

Unit	Symbol	Value in Grams
Milligram	mg	0.001 g
Gram	g	1 g
Kilogram	kg	1,000 g
Metric Ton	t	1,000,000 g

Weight Conversion Table

From	To	Multiply By
Ounces	Grams	28.3495
Pounds	Kilograms	0.453592
Stones	Kilograms	6.35029
Short Tons	Kilograms	907.185
Grams	Ounces	0.035274
Kilograms	Pounds	2.20462
Kilograms	Stones	0.157473
Metric Tons	Pounds	2,204.62

Volume Units

Imperial/US Customary

Unit	Symbol	Value in US Gallons	Value in Liters
US Teaspoon	us_tsp	1/768 gal	0.00493 L
US Tablespoon	us_tbsp	1/256 gal	0.01479 L
US Fluid Ounce	us_floz	1/128 gal	0.02957 L
US Cup	us_cup	1/16 gal	0.23659 L
US Pint	us_pt	1/8 gal	0.47318 L
US Quart	us_qt	1/4 gal	0.94635 L
US Gallon	us_gal	1 gal	3.78541 L

Metric

Unit	Symbol	Value in Liters
Milliliter	mL	0.001 L
Centiliter	cL	0.01 L
Deciliter	dL	0.1 L
Liter	L	1 L
Kiloliter	kL	1,000 L
Cubic Meter	m³	1,000 L

Volume Conversion Table

From	To	Multiply By
US Gallons	Liters	3.78541
Liters	US Gallons	0.264172
UK Gallons	Liters	4.54609
Liters	UK Gallons	0.219969
US Cups	Milliliters	236.588
Milliliters	US Cups	0.00422675
US Fluid Ounces	Milliliters	29.5735
Milliliters	US Fluid Ounces	0.033814

Temperature Units

Scale	Symbol	Freezing Point	Boiling Point
Celsius	°C	0°C	100°C
Fahrenheit	°F	32°F	212°F
Kelvin	K	273.15 K	373.15 K

Temperature Conversion Table

From	To	Formula
Celsius	Fahrenheit	°F = (°C × 9/5) + 32
Fahrenheit	Celsius	°C = (°F − 32) × 5/9
Celsius	Kelvin	K = °C + 273.15
Kelvin	Celsius	°C = K − 273.15
Fahrenheit	Kelvin	K = (°F − 32) × 5/9 + 273.15
Kelvin	Fahrenheit	°F = (K − 273.15) × 9/5 + 32

Common Temperature Values

Description	°C	°F	K
Absolute Zero	-273.15°C	-459.67°F	0 K
Water Freezes	0°C	32°F	273.15 K
Room Temperature	20-22°C	68-72°F	293-295 K
Body Temperature	37°C	98.6°F	310.15 K
Water Boils	100°C	212°F	373.15 K

Speed Units

Unit	Symbol	Value in m/s	Common Use
Meter per second	m/s	1 m/s	Science
Kilometer per hour	km/h	0.2778 m/s	Road speeds (worldwide)
Mile per hour	mph	0.4470 m/s	Road speeds (US)
Knot	kn	0.5144 m/s	Aviation, maritime
Foot per second	ft/s	0.3048 m/s	Engineering

Speed Conversion Table

From	To	Multiply By
km/h	mph	0.621371
mph	km/h	1.60934
m/s	km/h	3.6
km/h	m/s	0.277778
m/s	mph	2.23694
mph	m/s	0.44704
Knots	km/h	1.852
km/h	Knots	0.539957
Knots	mph	1.15078
mph	Knots	0.868976

Area Units

Unit	Symbol	Value in m²	Common Use
Square Millimeter	mm²	0.000001 m²	Microscopic
Square Centimeter	cm²	0.0001 m²	Small surfaces
Square Meter	m²	1 m²	Standard unit
Square Kilometer	km²	1,000,000 m²	Geographic
Square Foot	ft²	0.0929 m²	Real estate (US)
Square Yard	yd²	0.8361 m²	Landscaping
Acre	ac	4,046.86 m²	Land, farming
Hectare	ha	10,000 m²	Agriculture
Square Mile	mi²	2,589,988 m²	Geographic

Area Conversion Table

From	To	Multiply By
Square Meters	Square Feet	10.7639
Square Feet	Square Meters	0.092903
Hectares	Acres	2.47105
Acres	Hectares	0.404686
Square Kilometers	Square Miles	0.386102
Square Miles	Square Kilometers	2.58999
Acres	Square Meters	4,046.86
Hectares	Square Meters	10,000

Time Units

Unit	Symbol	Value in Seconds
Second	s	1 s
Minute	min	60 s
Hour	hr	3,600 s
Day	d	86,400 s
Week	wk	604,800 s
Year	yr	31,536,000 s

Time Conversion Table

From	To	Multiply By
Seconds	Minutes	0.0166667
Minutes	Hours	0.0166667
Hours	Days	0.0416667
Days	Hours	24
Hours	Minutes	60
Minutes	Seconds	60

Pressure Units

Unit	Symbol	Value in Pa	Common Use
Pascal	Pa	1 Pa	Standard unit
Kilopascal	kPa	1,000 Pa	Tires, weather
Megapascal	MPa	1,000,000 Pa	Engineering
Bar	bar	100,000 Pa	Tires, industry
Atmosphere	atm	101,325 Pa	Chemistry
PSI	psi	6,894.76 Pa	Tires (US)
mmHg	mmHg	133.322 Pa	Blood pressure
Torr	torr	133.322 Pa	Vacuum

Pressure Conversion Table

From	To	Multiply By
PSI	kPa	6.89476
kPa	PSI	0.145038
atm	kPa	101.325
kPa	atm	0.00986923
Bar	kPa	100
kPa	Bar	0.01
mmHg	kPa	0.133322
Torr	kPa	0.133322

Energy Units

Unit	Symbol	Value in Joules	Common Use
Joule	J	1 J	Standard unit
Kilojoule	kJ	1,000 J	Food energy
Megajoule	MJ	1,000,000 J	Engineering
Calorie	cal	4.184 J	Food energy
Kilocalorie	kcal	4,184 J	Food labels
BTU	BTU	1,055.06 J	Heating/cooling
Kilowatt-hour	kWh	3,600,000 J	Electricity

Energy Conversion Table

From	To	Multiply By
Joules	Calories	0.239006
Calories	Joules	4.184
Joules	BTU	0.000947817
BTU	Joules	1,055.06
kWh	Joules	3,600,000
Joules	kWh	0.000000277778
kcal	kJ	4.184
kJ	kcal	0.239006

Power Units

Unit	Symbol	Value in Watts	Common Use
Watt	W	1 W	Standard unit
Milliwatt	mW	0.001 W	Electronics
Kilowatt	kW	1,000 W	Appliances, cars
Megawatt	MW	1,000,000 W	Power plants
Gigawatt	GW	1,000,000,000 W	Large power plants
Horsepower	hp	745.7 W	Cars, engines

Power Conversion Table

From	To	Multiply By
Kilowatts	Watts	1,000
Watts	Kilowatts	0.001
Horsepower	Watts	745.7
Watts	Horsepower	0.00134102
Megawatts	Kilowatts	1,000
Gigawatts	Megawatts	1,000

Data Storage Units

Unit	Symbol	Value in Bytes	Common Use
Bit	b	0.125 bytes	Data transmission
Byte	B	1 byte	Standard unit
Kilobyte	KB	1,000 B	Small files
Megabyte	MB	1,000,000 B	Photos, music
Gigabyte	GB	1,000,000,000 B	Videos, games
Terabyte	TB	1,000,000,000,000 B	Hard drives
Petabyte	PB	1,000,000,000,000,000 B	Data centers

Data Conversion Table

From	To	Multiply By
Bytes	Kilobytes	0.001
Kilobytes	Megabytes	0.001
Megabytes	Gigabytes	0.001
Gigabytes	Terabytes	0.001
Terabytes	Petabytes	0.001
KB	MB	0.001
MB	GB	0.001
GB	TB	0.001

Everyday Measurement Quick Guide

Cooking

Ingredient	Common Measurement	Metric Equivalent
Flour	1 cup	120-140 g
Sugar	1 cup	200 g
Butter	1 stick	113 g
Water	1 cup	240 mL
Oil	1 tablespoon	15 mL
Salt	1 teaspoon	6 g

Body Measurements

Measurement	Imperial	Metric
Height	5′ 9″	175 cm
Weight	150 lb	68 kg
Temperature	98.6°F	37°C
Blood Pressure	120/80 mmHg	—

Travel

Measurement	Imperial	Metric
Speed Limit (Highway)	65 mph	105 km/h
Distance	100 miles	161 km
Fuel Tank	15 gallons	57 L
Luggage Limit	50 lb	23 kg

How to Use the Unit Converter

Select the category — Length, Weight, Volume, Temperature, Speed, etc.
Choose your input unit — e.g., mi (mile) or kg (kilogram)
Choose your output unit — e.g., km (kilometer) or lb (pound)
Enter the value — Type the number you want to convert
Get the result — Instant, accurate conversion

Available Categories

The converter supports all 15+ categories:

Category	Example Units
Length	m, ft, in, km, mi, cm, mm, yd, nmi
Weight	kg, lb, g, oz, st, T, t
Volume	L, gal, mL, cup, pint, quart, m³
Area	m², ft², ac, ha, km², mi²
Speed	km/h, mph, m/s, kn, ft/s
Temperature	°C, °F, K
Time	s, min, hr, d, wk
Pressure	Pa, kPa, psi, atm, bar
Energy	J, cal, BTU, kWh, kJ
Power	W, kW, MW, hp
Data Rate	bps, kbps, Mbps, Gbps
Storage	B, KB, MB, GB, TB
Frequency	Hz, kHz, MHz, GHz
Angle	deg, rad
Fuel Economy	mpg, L/100km
Color	Hex, RGB, Decimal

Frequently Asked Questions

Q: What is the most common unit conversion?

Length conversions (inches to cm, miles to km) and temperature conversions (°F to °C) are among the most common.

Q: How many inches are in a foot?

1 foot = 12 inches

Q: How many ounces are in a pound?

1 pound = 16 ounces

Q: How many cups are in a gallon?

1 US gallon = 16 cups

Q: How do I convert Celsius to Fahrenheit?

°F = (°C × 9/5) + 32

Q: How do I convert Fahrenheit to Celsius?

°C = (°F − 32) × 5/9

Q: How many miles are in a kilometer?

1 km = 0.621371 miles

Q: How many kilometers are in a mile?

1 mile = 1.60934 km

Q: What is the difference between US and UK gallons?

US gallon = 3.785 L, UK gallon = 4.546 L. UK gallon is about 20% larger.

Q: How do I convert units quickly?

Use our free unit converter at EasyConvertUnits.com

Try the Unit Converter

Ready to convert any unit? Use our free unit converter at:

https://www.easyconvertunits.com/

It supports all common measurement units with instant, accurate conversions and a clean, easy-to-use interface.

Final Thoughts

Understanding common measurement units and their conversions is an essential life skill. Whether you're cooking, traveling, building, or studying, knowing how to convert between units saves time, prevents mistakes, and helps you communicate effectively across different measurement systems.

Key takeaways:

Length: 1 mile = 1.609 km, 1 inch = 2.54 cm
Weight: 1 kg = 2.205 lb, 1 lb = 0.454 kg
Volume: 1 gal = 3.785 L, 1 cup = 236.6 mL
Temperature: °F = (°C × 9/5) + 32
Speed: 1 mph = 1.609 km/h
Use a converter tool for precision and speed

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