You’re traveling in Europe and the road sign says 120 km to your destination. How far is that in miles? Or you’re buying a couch online and it’s listed as 2.1 meters long. Will it fit in your living room?
Whether you’re traveling, shopping internationally, or just trying to understand a recipe from another country, length conversions come up constantly.
The Essential Conversion Factors
For everyday use, these are the key numbers to know.
Inches and centimeters: 1 inch = 2.54 cm. Or flip it: 1 cm = 0.394 inches. Quick mental math: divide centimeters by 2.5 for a rough inch estimate.
Feet and meters: 1 foot = 0.3048 meters. 1 meter = 3.281 feet. Quick trick: a meter is a little more than 3 feet — about 3 feet 3 inches.
Miles and kilometers: 1 mile = 1.609 km. 1 km = 0.621 miles. Quick trick: multiply km by 0.6 to get miles, or multiply miles by 1.6 to get km.
Height Conversions
Height is one of the most common conversions people search for, especially on dating apps and international forms.
150 cm = 4’11”. 155 cm = 5’1”. 160 cm = 5’3”. 165 cm = 5’5”. 170 cm = 5’7”. 175 cm = 5’9”. 180 cm = 5’11”. 185 cm = 6’1”. 190 cm = 6’3”. 195 cm = 6’5”. 200 cm = 6’7”.
The average American man is about 5’9” (175 cm) and the average American woman is about 5’4” (163 cm).
Distance for Runners
If you run or walk for fitness, knowing these distances helps translate workout data. One lap around a standard track is 400 meters (about 0.25 miles). A common running route of 3 miles is approximately 4.8 km.
For race distances: a 5K is 3.1 miles, a 10K is 6.2 miles, a half marathon is 13.1 miles (21.1 km), and a full marathon is 26.2 miles (42.2 km).
If your treadmill shows speed in km/h but you think in mph: 8 km/h is about 5 mph (a brisk walk), 10 km/h is 6.2 mph (a light jog), 12 km/h is 7.5 mph (a solid run), and 16 km/h is about 10 mph (a fast run).
Around the House
Furniture shopping internationally? A “queen size” bed in the US is 60 × 80 inches (152 × 203 cm). European double beds are often 140 × 200 cm (55 × 79 inches) — slightly narrower and shorter.
Standard US ceiling height is 8 feet (2.44 m) or 9 feet (2.74 m) in newer construction. A standard interior door is 6’8” tall (203 cm) and 2’8” to 3’0” wide (81-91 cm).
The Fibonacci Trick
Here’s a fun math trick for miles/kilometers: the Fibonacci sequence (1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89) roughly converts between the two. Consecutive Fibonacci numbers approximate miles-to-km conversions: 5 miles ≈ 8 km, 8 miles ≈ 13 km, 13 miles ≈ 21 km. It works because the ratio between consecutive Fibonacci numbers approaches 1.618, close to the 1.609 km/mile conversion.
Convert Anything
Our free Length Converter handles instant conversions between inches, feet, yards, miles, millimeters, centimeters, meters, and kilometers. No formulas needed.