Inch to CM Converter
Plain inches, decimals, fractions such as 5 1/2, or feet and inches such as 5 ft 9.
Result
0cm
Enter a value to start.
- Millimetres
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- Metres
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- Feet and inches
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One inch equals exactly 2.54 centimetres. Type any number into the box above and you get the answer in centimetres, millimetres and metres straight away. You can enter plain inches or feet and inches, and you can flip the tool round to work the other way. This tool is built for anyone measuring a height, TV, waist size or a piece of timber.
How to Convert Inches to CM (The Formula)
The math is one small sum. Multiply the inches by 2.54.
cm = inches × 2.54
To go the other way, divide instead.
inches = cm ÷ 2.54
Here are three worked examples with every step shown
- 7 inches 7 × 2.54 = 17.78 cm
- 32 inches (a small TV) 32 × 2.54 = 81.28 cm
- 5 ft 9 in (about average for a UK man) 5 × 12 = 60, then 60 + 9 = 69 inches. 69 × 2.54 = 175.26 cm.
The number 2.54 is not a rough guess. One inch is defined as exactly 2.54 cm, which is exactly 25.4 mm. That's the legal definition, so the sum gives you a true answer not an estimate.
How to Convert CM to Inches
Divide by 2.54. Take 180 cm as an example.
180 ÷ 2.54 = 70.87 inches
Now turn that into feet and inches. Divide the inches by 12 to get whole feet, and whatever is left over is your inches.
70.87 ÷ 12 = 5 with 10.87 left over, so 180 cm = 5 ft 10.87 in, near enough to 5 ft 11 in.
Quick Mental Maths Shortcut
No phone to hand? Use this.
Inches to cm: multiply by 2.5, then add 2% of that answer. For 20 inches: 20 × 2.5 = 50, and 2% of 50 is 1, so 50 + 1 = 51 cm. The true answer is 50.8 cm, so the result is out by less than 0.5%.
Cm to inches: divide by 2.5, then take off 2%. For 100 cm: 100 ÷ 2.5 = 40, and 2% of 40 is 0.8, so 40 − 0.8 = 39.2 inches. The true answer is 39.37 inches.
This trick is for quick estimating of a shelf in a shop, nothing more. About to cut something, use the converter.
Inches to CM Conversion Chart
Whole Inches (1 to 40)
| Inches | Centimetres |
|---|---|
| 1 | 2.54 |
| 2 | 5.08 |
| 3 | 7.62 |
| 4 | 10.16 |
| 5 | 12.7 |
| 6 | 15.24 |
| 7 | 17.78 |
| 8 | 20.32 |
| 9 | 22.86 |
| 10 | 25.4 |
| 11 | 27.94 |
| 12 | 30.48 |
| 13 | 33.02 |
| 14 | 35.56 |
| 15 | 38.1 |
| 16 | 40.64 |
| 17 | 43.18 |
| 18 | 45.72 |
| 19 | 48.26 |
| 20 | 50.8 |
| 21 | 53.34 |
| 22 | 55.88 |
| 23 | 58.42 |
| 24 | 60.96 |
| 25 | 63.5 |
| 26 | 66.04 |
| 27 | 68.58 |
| 28 | 71.12 |
| 29 | 73.66 |
| 30 | 76.2 |
| 31 | 78.74 |
| 32 | 81.28 |
| 33 | 83.82 |
| 34 | 86.36 |
| 35 | 88.9 |
| 36 | 91.44 |
| 37 | 93.98 |
| 38 | 96.52 |
| 39 | 99.06 |
| 40 | 101.6 |
Fractions of an Inch (tape measure sizes)
A UK tape measure is marked in sixteenths, and a good one goes down to thirty seconds. Those short marks are where people get stuck, so here is every one of them. Millimetres are given too, because that is what most UK trades work in.
| Fraction | Inches (decimal) | Centimetres | Millimetres |
|---|---|---|---|
| 1/32 | 0.03125 | 0.0794 | 0.79 |
| 1/16 | 0.0625 | 0.1588 | 1.59 |
| 3/32 | 0.09375 | 0.2381 | 2.38 |
| 1/8 | 0.125 | 0.3175 | 3.18 |
| 5/32 | 0.15625 | 0.3969 | 3.97 |
| 3/16 | 0.1875 | 0.4763 | 4.76 |
| 7/32 | 0.21875 | 0.5556 | 5.56 |
| 1/4 | 0.25 | 0.635 | 6.35 |
| 5/16 | 0.3125 | 0.7938 | 7.94 |
| 3/8 | 0.375 | 0.9525 | 9.52 |
| 7/16 | 0.4375 | 1.1113 | 11.11 |
| 1/2 | 0.5 | 1.27 | 12.7 |
| 9/16 | 0.5625 | 1.4288 | 14.29 |
| 5/8 | 0.625 | 1.5875 | 15.88 |
| 11/16 | 0.6875 | 1.7463 | 17.46 |
| 3/4 | 0.75 | 1.905 | 19.05 |
| 13/16 | 0.8125 | 2.0638 | 20.64 |
| 7/8 | 0.875 | 2.2225 | 22.22 |
| 15/16 | 0.9375 | 2.3813 | 23.81 |
To use a fraction with a whole number, add the two rows. For example, 3 and 3/8 inches is 7.62 cm + 0.9525 cm = 8.57 cm.
Feet and Inches to CM (height chart)
| Height | Total inches | Centimetres |
|---|---|---|
| 4 ft 10 in | 58 | 147.32 |
| 4 ft 11 in | 59 | 149.86 |
| 5 ft 0 in | 60 | 152.4 |
| 5 ft 1 in | 61 | 154.94 |
| 5 ft 2 in | 62 | 157.48 |
| 5 ft 3 in | 63 | 160.02 |
| 5 ft 4 in | 64 | 162.56 |
| 5 ft 5 in | 65 | 165.1 |
| 5 ft 6 in | 66 | 167.64 |
| 5 ft 7 in | 67 | 170.18 |
| 5 ft 8 in | 68 | 172.72 |
| 5 ft 9 in | 69 | 175.26 |
| 5 ft 10 in | 70 | 177.8 |
| 5 ft 11 in | 71 | 180.34 |
| 6 ft 0 in | 72 | 182.88 |
| 6 ft 1 in | 73 | 185.42 |
| 6 ft 2 in | 74 | 187.96 |
| 6 ft 3 in | 75 | 190.5 |
| 6 ft 4 in | 76 | 193.04 |
| 6 ft 5 in | 77 | 195.58 |
| 6 ft 6 in | 78 | 198.12 |
Where You Actually Need Inch to CM Conversions in the UK
Screen sizes. TVs and monitors are sold by the diagonal in inches, but wall brackets and cabinet gaps are listed in cm. A 55 inch TV measures 139.7 cm corner to corner, though the body is about 123 cm wide. Measure your gap in cm before you buy.
Clothing and waist sizes. UK trousers are labelled in inches, European ones in cm. A 32 inch waist is 81.28 cm, and a 34 inch waist is 86.36 cm. Shop online across Europe and you will need to convert inches to cm every time.
Curtains, blinds and fabric. Most UK retailers now sell by the cm, but plenty of older curtain rails and poles were fitted in inches. A 66 inch rail is 167.64 cm, which is why so many ready made curtains come in that odd looking size.
Photo prints. The classic 6 x 4 in print is 15.24 x 10.16 cm. An 8 x 10 in print is 20.32 x 25.4 cm. Frames sold by European brands are listed in cm, so check before you order the mount.
Bikes. Frame sizes are often quoted in inches on mountain bikes and in cm on road bikes. A 17 inch frame is 43.18 cm, which sits between a small and a medium on most road bike charts.
Timber and DIY. Careful here. A "2 by 4" is a nominal name, not a real measurement. Once planed, it comes out at roughly 38 x 89 mm, not 50.8 x 101.6 mm. Always measure the actual piece.
Luggage. UK airlines publish cabin bag limits in cm, but many suitcases sold online are described in inches. A 22 inch cabin case is 55.88 cm tall, which already sits on the edge of most 55 cm allowances.
Rounding and Accuracy: When Does the Extra Decimal Matter?
For a height, a rough shelf measurement or anything just reading off, one decimal place is plenty. Nobody needs to know they are 175.26 cm rather than 175.3 cm.
For DIY, sewing and joinery, work in millimetres and keep two decimals. Small errors stack up. If you are 0.5 cm out on one cut and you make ten of them, you are 5 cm out by the end, and that is a visible gap.
Never round partway through. Do the whole sum with 2.54, then round the final answer.
Here is what sloppy rounding costs you. Use 2.5 instead of 2.54 across 100 inches and you get 250 cm instead of 254 cm. That is 4 cm missing, which would ruin a run of skirting board.
Inch and Centimetre: What They Actually Are
The Inch
The inch has been fixed at exactly 25.4 mm since the international yard and pound agreement of 1959, which the UK, United States, Canada, Australia, New Zealand and South Africa all signed. Before then the British inch and the American inch were very slightly different and in precision engineering that gap caused real problems. There are 12 inches in a foot and 36 in a yard.
The Centimetre
A centimetre is one hundredth of a metre, and it belongs to the SI metric system. Ten millimetres make a centimetre. Britain runs on a mixed system and always has done. Road signs are in miles, most people give their height in feet and inches and their weight in stones, yet school maths, the NHS and nearly all packaging use metric. That is exactly why a tool like this gets used every day.
