Height Converter

Height is quoted in centimetres on a passport, a medical record or a school form, and in feet and inches on dating profiles, in sports listings and in everyday speech across much of the English-speaking world. Anyone who moves between the two needs a quick and reliable conversion. This page gives the arithmetic, a chart of common heights, and the rounding rules that explain why you will see the same height written two slightly different ways.

The definitions

An inch is defined as exactly 2.54 centimetres. That was fixed by agreement among the English-speaking countries in 1959, replacing slightly different national inches. A foot is 12 inches, so:

1 foot = 12 × 2.54 = 30.48 cm

Because the figures are exact, a conversion has no measurement error in it. The only approximation is the rounding you choose when you write the answer down. Five feet is exactly 152.4 cm, six feet is exactly 182.88 cm, and each extra foot adds 30.48 cm.

Centimetres to feet and inches

Divide the centimetres by 2.54 to get the total inches, then split the inches into feet and a remainder by dividing by 12.

For 170 cm: 170 ÷ 2.54 = 66.93 inches. Dividing by 12 gives 5 with a remainder, since 5 × 12 = 60 and 66.93 − 60 = 6.93. So 170 cm is 5 feet 6.9 inches.

For 175 cm: 175 ÷ 2.54 = 68.90 inches, which is 5 feet 8.9 inches, very nearly 5 feet 9.

To express the inches as a fraction, the nearest eighth is the usual choice. The 0.929 of an inch in 5′ 6.929″ is 7.43 eighths, so the nearest eighth is 7, and the height is 5 feet 6⅞ inches. The calculator shows this as well as the decimal, since tape measures, tailors and carpenters work in fractions of an inch rather than tenths, and a reading of 6.9 inches is not something a tape can show.

Feet and inches to centimetres

Turn the feet into inches (× 12), add the loose inches, then multiply by 2.54.

For 5 feet 7 inches: 5 × 12 + 7 = 67 inches, and 67 × 2.54 = 170.18 cm.

For 6 feet 2 inches: 6 × 12 + 2 = 74 inches, and 74 × 2.54 = 187.96 cm.

The metres figure is the centimetres divided by 100, so 170.18 cm is 1.702 m. If you need a height in metres for a body mass index, use that value; the formula divides weight in kilograms by the height in metres squared, which for 1.70 m is 1.70 × 1.70 = 2.89.

A chart from 150 to 190 cm

Notice that heights ending in 5 and 0 cm often fall close to a whole inch (155, 160 and 165 are all within 0.1 inch), while the ones in between, such as 170 and 175, sit just under the next inch and are rounded up. That is a quirk of the inch being a little more than 2.5 cm.

Why one height has two spellings

A person who is 5 feet 7 inches tall will often say they are 170 cm, and a form that asks for centimetres will accept 170. The exact conversion of 5′ 7″ is 170.18 cm, and 170 cm is exactly 5′ 6.93″. These differ by 0.18 cm, under two millimetres, which is far smaller than the difference between a morning measurement and an evening one. Height changes across a day, by up to a centimetre or more, as the spinal discs compress under the weight of standing.

So when a document wants a figure in a particular unit, give it the way the document asks, rounding to the nearest whole centimetre or the nearest inch. If two documents disagree by a few millimetres because one was converted and the other measured, that is normal and rarely matters. Where it does matter, such as a form that checks a height limit, convert from the original measurement rather than converting a converted figure, so the rounding happens once.

Keeping the inches under twelve

A common slip is a result like "5 feet 12 inches". Inches should be always below 12, and 12 inches is a foot, so this is 6 feet. It happens when the inches are rounded up from 11.96 to 12.0 and the feet are not adjusted. The calculator carries the extra inch into the feet automatically: 71.96 inches rounds to 72.0, which it shows as 6 feet 0 inches. If you convert by hand, check the remainder after rounding.

The same care applies in reverse. If you enter 5 feet 14 inches, the tool treats it as 5 × 12 + 14 = 74 inches, which is 6 feet 2 inches, and gives the right centimetres. The hint on the inches field says so.

Heights in other contexts

Children. A child's height is plotted in centimetres on a growth chart. For the percentile and the expected adult height, the baby growth percentile calculator and the child height predictor work in centimetres, so a height given in feet and inches should be converted first.

Comparing people. To see how two heights look side by side, the height comparison tool draws them together.

Weight and BMI. Body mass index needs the height in metres, and a weight in kilograms. For a weight given in stones, the stone to kg converter does that step, and the BMI calculator then does the rest.

Doors, furniture and fittings. Measurements in a house are often in feet and inches in one catalogue and centimetres in another. A standard door is about 6 feet 8 inches high, which is 203.2 cm, and a ceiling of 8 feet is 243.84 cm.

A short way to estimate

For a rough conversion in your head, remember that 30 cm is nearly a foot (30.48) and 2.5 cm is nearly an inch (2.54). So 180 cm is about 6 feet (182.88 is closer to 6 feet exactly), and 150 cm is nearly 5 feet (152.4). The mental route is fine for a quick sense of scale and wrong by up to an inch for anything you need to put on a form, so use the exact calculation for those. If you convert often, learn two anchors: 152.4 cm is 5 feet and 182.88 cm is 6 feet.

What this calculator assumes

• One inch is exactly 2.54 cm, and one foot is 12 inches.
• Feet and inches are shown with the inches rounded to one decimal place, and any rounded-up 12 carries into the next foot.
• The fraction is the nearest eighth of an inch.
• Heights above 400 cm (13 feet) are treated as a mistake and not converted.
• Only length is converted; the tool does not assess whether a height is typical or healthy.