How to use the Height Converter
- Enter the feet portion of the height.
- Enter the remaining inches — use decimals for part-inches if needed.
- Read the centimetre value, which is what most medical and official forms want.
- Use the metre value for BMI and other formulae that expect SI units.
- To go the other way, enter zero feet and the centimetre figure divided by 2.54 as inches.
How the calculation works
Height is a length conversion with one wrinkle: it is customarily written as two numbers rather than one. The calculation combines them first — total inches equals feet times twelve plus inches — and then multiplies by exactly 2.54 to reach centimetres. Because the inch is defined as 25.4 mm exactly, no approximation enters anywhere in the chain.
The two-part format is where errors creep in. A height of 5 ft 9 in is 69 inches, not 5.9 of anything, and treating the inches as a decimal fraction of a foot produces an answer several centimetres out. Any spreadsheet handling mixed heights should store total inches or centimetres as a single number and format for display, never store the two-part string.
Consistency matters more than the conversion for downstream calculations. BMI expects metres, most clinical charts use centimetres, and US paperwork wants feet and inches. Converting once at the point of entry and storing a single canonical unit avoids the compounding rounding that appears when a value is converted back and forth repeatedly through a workflow.
total inches = feet × 12 + inches; centimetres = total inches × 2.54; metres = centimetres ÷ 100Source: International Yard and Pound Agreement (1959); NIST Special Publication 811.
Worked example
A medical form needs a height of 5 ft 11 in expressed in centimetres and metres.
- Enter 5 feet and 11 inches.
- Total inches: 5 × 12 + 11 = 71 in.
- Centimetres: 71 × 2.54 = 180.34 cm.
- Metres: 1.8034 m, which is the figure BMI needs.
5 ft 11 in is 180.3 cm, or 1.80 m — use the metre value directly in any BMI or body-surface-area formula.
Frequently asked questions
How many centimetres is 6 feet?+
182.88 cm, since 72 inches times 2.54 gives exactly 182.88.
How do I convert centimetres back to feet and inches?+
Divide by 2.54 for total inches, then divide by 12 for whole feet; the remainder is the inches. 175 cm is 68.9 in, or 5 ft 8.9 in.
Is 5.9 the same as 5 ft 9 in?+
No. 5 ft 9 in is 5.75 feet. Writing it as 5.9 overstates the height by nearly 2 cm.
Which unit does BMI need?+
Metres, if you use the metric formula of weight in kilograms divided by height in metres squared. The imperial version uses pounds and inches with a 703 multiplier.
Last reviewed September 1, 2026. We review this page whenever the underlying formula, tax year, published rate or standard changes.