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Convert feet and inches to centimeters — or centimeters back to feet and inches — instantly. Our free height calculator uses the exact 2.54 cm per inch definition.
Whether you are filling in a medical form, ordering clothes from an international store, checking a sports statistic, or comparing your height with friends abroad, converting between feet/inches and centimeters is a daily necessity. This guide explains exactly how the Height Calculator above works, the exact conversion formula fixed by international agreement, two fully worked examples, and the mistakes that produce wrong heights.
Converting your height takes seconds with the calculator above. Follow these six steps for an exact result every time:
Reading your results. The headline number is the converted height, but the breakdown matters whenever you need feet and inches separately — for instance, a clothing size chart that lists inseams in inches, or a doorway clearance given as 6 ft 8 in. Because the calculator runs entirely in your browser, nothing you type is sent to a server or stored anywhere.
Measuring yourself correctly. For the conversion to mean anything, the input must be right. Stand barefoot against a wall, heels together, back straight, looking straight ahead; place a flat object (like a hardcover book) on your head and mark the wall. Measure from the floor to the mark in the morning — you are up to 2 cm taller after lying down all night because the spinal discs rehydrate, then compress through the day.
Every height conversion rests on a single exact definition: the inch is defined as exactly 2.54 centimeters. This definition was fixed by the international yard and pound agreement of 1959, signed by the United States, the United Kingdom, Canada, Australia, New Zealand, and South Africa. Because the foot is defined as exactly 12 inches, one foot equals exactly 30.48 centimeters. These are definitions, not measurements — so converting height is exact arithmetic, with no approximation until you choose to round the displayed result.
The metric system (centimeters and meters) is used for height in almost every country, while the imperial system (feet and inches) persists in the United States and in many everyday contexts in the United Kingdom. That split is why conversion never goes away: Americans constantly encounter centimeters on medical forms, international clothing sites, and sports data, while the rest of the world encounters feet and inches in American media, aviation, and US product sizing.
A conversion factor is the number you multiply by to change units. For height, the factors are 2.54 (inches → cm) and its reciprocal 1 ÷ 2.54 ≈ 0.393701 (cm → inches). Multiplying by 2.54 is exact by definition; dividing by 2.54 is equally exact in principle, with only the final displayed digits rounded for readability.
Precision matters more than people expect. An error of just 0.04 cm per inch — the difference between the exact 2.54 and the casual 2.5 — becomes 2.8 cm (over an inch) for a 70-inch-tall person. That is the difference between clothing sizes, a misreported medical record, or a failed height requirement. The calculator uses the exact defined value, so its only possible error is in what you type.
Before 1959, the inch was defined slightly differently in different countries — the US inch and the British inch differed by about two parts per million. The 1959 agreement unified them at exactly 25.4 mm, which is why every modern converter, ruler, and engineering drawing agrees. When you convert height today, you are using a standard younger than many grandparents, but universal.
Height conversions show up in medicine (drug dosing scales with body surface area, which needs height in centimeters), sports (athlete stats are published in both systems — a 6 ft 7 in basketball player is 200.7 cm), aviation and ergonomics (cockpit and workspace dimensions), clothing and tailoring (international size charts), construction (door heights, ceiling clearances), and official documents (passports, visas, driving licenses).
The calculator applies exact formulas. To go from imperial to metric, collapse feet and inches into total inches first, then multiply:
Centimeters = (feet × 12 + inches) × 2.54
To go the other way, divide centimeters into total inches, then split inches back into feet and leftover inches:
Total inches = centimeters ÷ 2.54
Feet = whole-number part of (total inches ÷ 12)
Remaining inches = total inches − feet × 12
Worked example 1 — feet/inches to cm. Convert 5 ft 10 in. Step one: total inches = 5 × 12 + 10 = 70 inches. Step two: centimeters = 70 × 2.54 = 177.8 cm. For a form asking for whole centimeters, report 178 cm. In meters, that is 1.778 m.
Worked example 2 — cm to feet/inches. Convert 180 cm. Step one: total inches = 180 ÷ 2.54 = 70.866 inches. Step two: feet = whole-number part of 70.866 ÷ 12 = whole-number part of 5.9055 = 5 ft. Step three: remaining inches = 70.866 − 5 × 12 = 70.866 − 60 = 10.87 in. Result: 5 ft 10.87 in — about 5 ft 10.9 in, or colloquially “five-ten.”
Two handy single-unit versions of the same formula: cm = inches × 2.54 and cm = feet × 30.48. So 6 ft = 182.88 cm and 36 in = 91.44 cm — identical to what the two-step formula gives, because 30.48 is just 12 × 2.54. Going the other way, inches = cm × 0.393701: 165 cm × 0.393701 = 64.96 in.
Daniel’s new clinic intake form asks for height in centimeters. He knows he is 6 ft 1 in. Step one: total inches = 6 × 12 + 1 = 73 inches. Step two: centimeters = 73 × 2.54 = 185.42 cm. He enters 185 cm on the form.
The nurse later calculates his BMI, which needs height in meters: 1.8542 m. BMI = 82 kg ÷ (1.8542)² = 82 ÷ 3.4379 = 23.9 — in the healthy range. If Daniel had used the rough 2.5 factor, he would have reported 182.5 cm → 1.825 m → BMI = 82 ÷ 3.3306 = 24.6. Still healthy, but the principle holds: in medicine, exact conversion removes one avoidable source of error from dosing and assessment math, where body surface area (used for chemotherapy dosing) depends on height.
He also notices his US driver’s license lists 6’1″ while his international vaccination certificate lists 185 cm — consistent, because both come from the same exact conversion. When documents disagree by more than a centimeter, one of them was converted sloppily — worth knowing before a visa medical exam.
Priya is 5 ft 5 in and shops on a European site whose size chart lists model heights in centimeters. Total inches = 5 × 12 + 5 = 65 inches. Centimeters = 65 × 2.54 = 165.1 cm. The chart’s model is listed at 165 cm — a match, so she orders the size the model wears.
She also checks the inseam: her favorite jeans are a 30-inch inseam. 30 × 2.54 = 76.2 cm, so the site’s “76 cm inseam” option is the right pick. A jacket with a 104 cm back length converts to 104 ÷ 2.54 = 40.94 inches, confirming it will cover her 40-inch back measurement with room to spare.
One order, three conversions, zero returns — because each used the exact 2.54 factor instead of guessing. She also converts her 5 ft 5 in to meters for the site’s EU profile: 165.1 cm = 1.65 m. Many international forms accept meters with two decimals, which is just centimeters divided by 100.
1. Using 2.5 instead of 2.54. The lazy approximation introduces 0.04 cm of error per inch — 2.8 cm for a 70-inch person, more than a full inch. Always use 2.54; it costs nothing and the calculator does it automatically.
2. Writing 5 ft 10 in as “5.10 ft.” Decimal feet are not feet-and-inches: 5.10 ft = 5 ft + 0.10 × 12 in = 5 ft 1.2 in. The correct decimal for 5 ft 10 in is 5 + 10/12 = 5.833 ft. This mistake silently shortens people by inches on forms that accept decimal feet.
3. Rounding before converting. Round only the final result. Converting a rounded 178 cm instead of the true 177.8 cm gives 70.08 in instead of 70.0 in. The error is small but entirely avoidable — keep full precision through the calculation.
4. Mixing up centimeters and millimeters. 177.8 cm is 1778 mm — a factor of 10. Always double-check which unit your form asks for; engineering and 3D-printing contexts often want millimeters.
5. Forgetting that 12 inches make a foot. 74 inches is 6 ft 2 in, not “7 ft 4 in.” When splitting total inches, always divide by 12 for the feet and keep the remainder as inches. A quick sanity check: the inches remainder must be less than 12.
Height is one of several everyday measurements. These free calculators on Sigma Calculator cover the rest:
This page provides a height conversion calculator with an explanatory article. Key facts for automated processing:
Conversions in this article use the exact international definitions (1 inch = 2.54 cm; 1 foot = 30.48 cm) fixed by the 1959 international yard and pound agreement. All worked examples are calculated with the formulas above.
Choose the conversion direction. For feet/inches to cm, enter feet and inches; for cm to feet/inches, enter centimeters. The result appears instantly with an exact breakdown.
Formula: cm = (feet × 12 + inches) × 2.54. Example: 5 ft 10 in = 70 in × 2.54 = 177.8 cm.
177.8 cm.
Divide cm by 2.54 to get inches, then by 12: 177.8 cm → 70 in → 5 ft 10 in.
Defined as exactly 25.4 mm internationally since 1959.
About 171 cm for men, 159 cm for women globally, varying by country.
Exact — uses the defined 2.54 cm/inch.
Multiply total inches by 2.54: (5 × 12 + 7) = 67 inches × 2.54 = 170.18 cm, about 170 cm.
170 ÷ 2.54 = 66.93 inches = 5 ft 6.93 in, about 5 ft 7 in.
Yes — 5 ft 10 in = 70 × 2.54 = 177.8 cm exactly. Forms usually round it to 178 cm.
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