Feet and inches to meters
Type feet, inches and a fraction of an inch, or metres, centimetres or millimetres: the other side updates as you type, and the tape shows both readings on one scale. The inch is exactly 2.54 cm, so the metric answer is exact.
Feet and inches to metres
1 inch is exactly 2.54 cm and 1 foot exactly 0.3048 m, so feet and inches convert to metric exactly. Metric to feet and inches rounds to the nearest 1/16 in, as a tape reads.
In metric
2.032 m
- Metres
- 2.032
- Centimetres
- 203.2
- Millimetres
- 2,032
- Feet
- 6.6667
- Inches
- 80
On a tape measure
The formula
- Total inches: feet × 12 + inches + the fraction (a sixteenth is 0.0625 in).
- To metric: inches × 2.54 = centimetres, exactly. Divide by 100 for metres; multiply by 10 for millimetres.
- Back to feet and inches: centimetres ÷ 2.54 = inches; whole twelves are feet, and what is left is rounded to the nearest 1/16 in, the finest mark on most tapes.
Worked example
A room 12 ft 6½ in long: 12 × 12 + 6.5 = 150.5 in, and 150.5 × 2.54 = 382.27 cm, or 3.8227 m. The other way, a 2.4 m European ceiling is 240 ÷ 2.54 = 94.488 in: 7 ft (84 in) and 10.488 in left, which rounds to 7 ft 10½ in, a little under the 8 ft ceiling usual in US houses.
| What | Imperial | Metres | Centimetres |
|---|---|---|---|
| Interior door height | 80 in (6′ 8″) | 2.032 m | 203.2 cm |
| Bedroom door width | 30 in (2′ 6″) | 0.762 m | 76.2 cm |
| Bathroom or bedroom door | 32 in (2′ 8″) | 0.8128 m | 81.28 cm |
| Front door width | 36 in (3′) | 0.9144 m | 91.44 cm |
| IRC minimum ceiling | 7 ft | 2.1336 m | 213.36 cm |
| Typical ceiling | 8 ft | 2.4384 m | 243.84 cm |
| Taller ceiling | 9 ft | 2.7432 m | 274.32 cm |
| Kitchen counter height | 36 in (3′) | 0.9144 m | 91.44 cm |
| Base cabinet depth | 24 in (2′) | 0.6096 m | 60.96 cm |
| Queen mattress | 60 × 80 in | 1.524 × 2.032 m | 152.4 × 203.2 cm |
| King mattress | 76 × 80 in | 1.9304 × 2.032 m | 193.04 × 203.2 cm |
The sizes are the usual US ones from our guides: standard door sizes, ceiling heights, kitchen cabinet dimensions and king bed room size.
Reading a tape in both systems
- Imperial marks halve down: the long line is the inch, then ½, ¼, ⅛ and 1/16. Count the sixteenths from the last whole inch and reduce the fraction (6/16 is ⅜).
- Metric marks are every millimetre, with a longer one every 5 mm and a number every centimetre. Write metric lengths in millimetres on drawings to avoid the decimal point going astray.
- Don't round twice. Convert the whole length once, from the original measurement, rather than converting a rounded figure back.
- Mind the hook: a tape's end hook slides by its own thickness so inside and outside measurements both read true; a bent hook throws every reading off by the same amount.
Draw it once, read it both ways
A FloorGen plan can show feet and inches (to 1/16 in) or metric (to 1 mm), and switching the project's units relabels every dimension without moving a wall. Metric vs imperial floor plans covers working across the two.
Questions
How many centimetres are in a foot?
Exactly 30.48 cm: 12 inches × 2.54 cm. A metre is about 3.2808 ft, or 3 ft 3⅜ in to the nearest sixteenth.
What is 5 ft 10 in in centimetres?
177.8 cm. 5 × 12 + 10 = 70 in, and 70 × 2.54 = 177.8.
How do I convert inches with fractions to millimetres?
Turn the fraction into a decimal first (⅜ = 0.375), add it to the inches, then multiply by 25.4. For 1⅜ in: 1.375 × 25.4 = 34.925 mm.
Is the conversion exact?
From feet and inches to metric, yes: the inch has been defined as exactly 2.54 cm since 1959. From metric to feet and inches, the calculator rounds to the nearest 1/16 in and says so with ≈.
What is the difference between a survey foot and a foot?
The U.S. survey foot was about 2 parts per million longer than the international foot. NIST deprecated it from 2023; it only mattered over survey distances of miles, never for a room.