How do I convert kg to lbs?

Multiply kilograms by 2.2046226218. For example, 70 kg × 2.2046 = 154.32 lbs.

How many liters in a gallon?

1 US gallon = 3.78541 liters. 1 UK imperial gallon = 4.54609 liters.

How do I convert Celsius to Fahrenheit?

Use the formula: °F = (°C × 9/5) + 32. For example, 100°C = 212°F.

Free Unit Converter | Length, Weight, Volume & More

Q: How many centimeters are in an inch?

1 inch = 2.54 centimeters exactly. So to convert inches to cm, multiply by 2.54.

From

To

—

Common Length References

Unit	= Meters	= Inches	= Feet
1 mm	0.001 m	0.03937 in	0.00328 ft
1 cm	0.01 m	0.3937 in	0.03281 ft
1 m	1 m	39.3701 in	3.28084 ft
1 km	1,000 m	39,370.1 in	3,280.84 ft
1 in	0.0254 m	1 in	0.08333 ft
1 ft	0.3048 m	12 in	1 ft
1 yd	0.9144 m	36 in	3 ft
1 mi	1,609.34 m	63,360 in	5,280 ft

From

To

—

📊 Full Weight Chart →

Weight Unit Reference

Unit	= kg	= lbs	= oz
1 g	0.001 kg	0.002205 lbs	0.03527 oz
1 oz	0.02835 kg	0.0625 lbs	1 oz
1 lb	0.45359 kg	1 lbs	16 oz
1 kg	1 kg	2.20462 lbs	35.274 oz
1 stone	6.35029 kg	14 lbs	224 oz
1 metric ton	1,000 kg	2,204.62 lbs	35,274 oz

From

To

—

Volume Reference Chart

Unit	= Liters	= US gal	= fl oz
1 mL	0.001 L	0.000264 gal	0.03381 fl oz
1 fl oz	0.02957 L	0.0078125 gal	1 fl oz
1 cup	0.23659 L	0.0625 gal	8 fl oz
1 pint	0.47318 L	0.125 gal	16 fl oz
1 quart	0.94635 L	0.25 gal	32 fl oz
1 L	1 L	0.26417 gal	33.814 fl oz
1 US gal	3.78541 L	1 gal	128 fl oz
1 UK gal	4.54609 L	1.20095 gal	153.72 fl oz

From

To

—

Water Freezes

0°C

32°F / 273.15K

Body Temp

37°C

98.6°F / 310.15K

Water Boils

100°C

212°F / 373.15K

Oven (Moderate)

180°C

356°F / 453.15K

Temperature Conversion Formulas

From	To	Formula
°C	°F	(°C × 9/5) + 32
°F	°C	(°F − 32) × 5/9
°C	K	°C + 273.15
K	°C	K − 273.15
°F	K	(°F + 459.67) × 5/9

From

To

—

Area Reference Chart

Unit	= m²	= ft²	Notes
1 cm²	0.0001 m²	0.001076 ft²	Fingernail-sized
1 ft²	0.0929 m²	1 ft²	Floor tile
1 m²	1 m²	10.7639 ft²	Desk surface
1 yd²	0.8361 m²	9 ft²	—
1 acre	4,046.86 m²	43,560 ft²	Football field ~1.3 acres
1 ha	10,000 m²	107,639 ft²	= 2.471 acres
1 km²	1,000,000 m²	10,763,910 ft²	= 247.1 acres
1 mi²	2,589,988 m²	27,878,400 ft²	= 640 acres

📖 Reference Guide

Unit Converter — Complete Guide

Metric vs imperial systems, conversion factors, and practical tips

The metric system (SI) is the international standard used by 195+ countries for science, medicine, trade, and everyday life. It is a base-10 system: every unit scales by factors of 10, making conversions straightforward.

The imperial / US customary system is used primarily in the United States (and partially in the UK for body weight and road distances). It uses non-decimal units: 12 inches to a foot, 16 ounces to a pound, 8 pints to a gallon.

This all-in-one converter covers the five most-searched unit categories: length, weight, volume, temperature, and area. All conversions use exact SI-defined factors where available (e.g., 1 inch = 2.54 cm exactly, 1 lb = 0.45359237 kg exactly).

Temperature is the exception — it requires a formula rather than a simple multiplication factor, because its scales have different zero points. Celsius, Fahrenheit, Kelvin, and Rankine all measure the same physical property using different reference systems.

Quick Mental Conversion Tips

📏

Length: 1 inch ≈ 2.5 cm; 1 foot ≈ 30 cm; 1 mile ≈ 1.6 km

⚖️

Weight: 1 kg ≈ 2.2 lbs; double the kg then add 10% for a quick estimate

💧

Volume: 1 liter ≈ 0.264 US gallons; 1 cup = 8 fl oz = 236.6 mL

🌡️

Temp: Double the °C, then add 30 for °F (rough); subtract 32, halve for °C

📐

Area: 1 acre ≈ 4,047 m² ≈ 0.4 ha; 1 ha = 10,000 m² = 2.47 acres

Frequently Asked Questions

Common unit conversion questions answered

How many centimeters are in an inch?

Exactly 2.54 centimeters. This is a defined exact value since 1959. So 1 inch = 2.54 cm, and 1 cm = 0.393701 inches.

How do I convert kilograms to pounds?

Multiply kilograms by 2.2046226218. For a quick estimate, multiply by 2 then add 10%. Example: 70 kg × 2.2046 = 154.32 lbs. For the reverse, multiply lbs by 0.45359237.

How many liters are in a US gallon?

1 US gallon = 3.78541 liters exactly. Note: the UK imperial gallon is larger at 4.54609 liters.

What is the formula to convert Celsius to Fahrenheit?

°F = (°C × 9/5) + 32. So 0°C = 32°F (water freezes), 100°C = 212°F (water boils), 37°C = 98.6°F (body temperature).

How many square feet in an acre?

43,560 square feet in one acre. In metric, 1 acre = 4,046.86 m² ≈ 0.4047 hectares.

Which countries use the imperial system?

Primarily the United States, Myanmar, and Liberia officially use the imperial/US customary system. The UK uses a mix: metric for most things but miles for roads, pints for beer, and stones/pounds for body weight.