Feet & Inches to Cm Converter
Convert feet and inches to centimeters and back — height conversions like 5'9" to cm, instantly.
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Feet & Inches ↔ Centimeters
Definitions: 1 foot = 30.48 cm, 1 inch = 2.54 cm, and 1 foot = 12 inches. Heights written like 5'9" mean 5 feet 9 inches: (5 × 30.48) + (9 × 2.54) = 175.3 cm. Enter feet and inches on one side or centimeters on the other — both convert live, with the meters value shown alongside so you don't need a second tool for metric-only contexts.
Because the ratio between feet and centimeters is fixed rather than approximate, the math never rounds unpredictably: multiplying by 30.48 or 2.54 gives the same result every time, whether you're converting a doorway, a piece of furniture, or a person's height. That consistency is exactly why the units translate cleanly across borders — a measurement taken in feet and inches in the US corresponds to one exact centimeter figure everywhere else, with no ambiguity about which historical "foot" was used to take it.
Good to Know
These figures aren't rounded for convenience — they're exact by international agreement. In 1959, the US, UK, Australia, Canada, New Zealand and South Africa signed the International Yard and Pound Agreement, fixing the inch at precisely 2.54 cm and the foot at precisely 30.48 cm across all six countries. Before that, each nation used a slightly different foot for official purposes; the US even kept a separate "survey foot" — a few parts per million longer than the new international foot — for land surveying and official maps, only retiring it for good in 2022 after more than sixty years of parallel use. The prime and double-prime marks in a height like 5'9" — ′ for feet, ″ for inches — are borrowed from a much older notation for arcminutes and arcseconds, angle subdivisions used in navigation, cartography and astronomy since the 18th century, long before anyone applied them to human height.
- Airplane economy seat width: roughly 1'5″–1'6″ (43–46 cm)
- Standard interior door height: about 6'8″ (203 cm)
- NBA average player height: around 6'6″ (198 cm)
- IKEA kitchen counter height: about 2'11″ (90 cm)
- Typical ceiling height in a US home: 8'0″ (244 cm)
Frequently Asked Questions
How tall is 5'9" in cm?
5 feet 9 inches = 175.3 cm, calculated as (5 × 30.48) + (9 × 2.54). Other common heights: 5'5" = 165.1 cm, 5'11" = 180.3 cm, 6'0" = 182.9 cm, 6'2" = 188 cm. Because the conversion factors are fixed exactly by international agreement, these figures come out identical regardless of source — there's no rounding drift between different calculators or reference tables.
How do I convert 170 cm to feet and inches?
Divide by 2.54 to get 66.9 inches total, then divide by 12 to split that into feet and remaining inches: 5 feet 6.9 inches, conventionally rounded and written 5'7". If you need more precision — for tailoring, furniture, or doorway clearance — keep the decimal as 5'6.9" instead of rounding up to the nearest whole inch.
Why do heights use quote marks, like in 5'9"?
The prime (′) and double-prime (″) marks are borrowed from a much older notation for arcminutes and arcseconds — subdivisions of an angle used in navigation, cartography and astronomy since the 18th century. ′ stands for feet, ″ for inches, so 5'9" reads as "5 feet, 9 inches." The same two symbols still appear in geographic coordinates today, which is closer to their original purpose.
Has an inch always been exactly 2.54 cm?
Not quite. Before the 1959 International Yard and Pound Agreement, each English-speaking country defined its own foot, so the same measurement could translate to a marginally different number of centimeters depending on where it was taken. The US also kept a separate "survey foot" — a few parts per million longer than the international foot — for land surveying, only officially retiring it in 2022. Today the everyday foot and inch have been identical worldwide for more than six decades.
Where are feet and inches still commonly used instead of cm?
Mainly in the United States, for everyday measurements like height, room dimensions, and TV or monitor screen sizes. Internationally, aviation is a notable holdout: altitude is reported in feet worldwide by convention, regardless of a country's usual measurement system. The UK, while officially metric, also still commonly states height and short distances in feet and inches.
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