Length Conversion Charts: Heights, Millimetres and Fractional Inches
Published November 3, 2026 · By Ahmad Parvez
Most length look-ups are one of three jobs: reading a height in centimetres as feet and inches, turning millimetres into the decimal inches a caliper or a spec sheet wants, or matching a fractional inch (the language of tape measures) to its metric size. Each gets its own chart here, with the formulas underneath for everything in between.
Height chart: centimetres to feet and inches
| cm | Feet & inches | cm | Feet & inches |
|---|---|---|---|
| 140 | 4 ft 7.1 in | 175 | 5 ft 8.9 in |
| 145 | 4 ft 9.1 in | 180 | 5 ft 10.9 in |
| 150 | 4 ft 11.1 in | 185 | 6 ft 0.8 in |
| 155 | 5 ft 1.0 in | 190 | 6 ft 2.8 in |
| 160 | 5 ft 3.0 in | 195 | 6 ft 4.8 in |
| 165 | 5 ft 5.0 in | 200 | 6 ft 6.7 in |
| 170 | 5 ft 6.9 in |
The formula: divide the centimetres by 2.54 to get total inches, then divide by 12 — the whole number is feet, the remainder is inches. 172 cm ÷ 2.54 = 67.7 in = 5 ft 7.7 in. Note that everyday speech rounds: someone 180 cm is usually called "five eleven" even though the chart says 5 ft 10.9 in.
Millimetres to decimal inches
| mm | Inches | mm | Inches |
|---|---|---|---|
| 1 | 0.0394 | 12 | 0.4724 |
| 2 | 0.0787 | 15 | 0.5906 |
| 3 | 0.1181 | 20 | 0.7874 |
| 4 | 0.1575 | 25 | 0.9843 |
| 5 | 0.1969 | 25.4 | 1.0000 |
| 6 | 0.2362 | 30 | 1.1811 |
| 8 | 0.3150 | 40 | 1.5748 |
| 10 | 0.3937 | 50 | 1.9685 |
Formula: inches = mm ÷ 25.4. Going the other way, inches = multiply by 25.4 — a 0.75 in bolt spacing is 19.05 mm.
Fractional inches to millimetres
Tape measures speak in sixteenths; metric drawings speak in millimetres. This is the translation table for the common fractions:
| Inches | mm | Inches | mm |
|---|---|---|---|
| 1/16 | 1.59 | 9/16 | 14.29 |
| 1/8 | 3.18 | 5/8 | 15.88 |
| 3/16 | 4.76 | 11/16 | 17.46 |
| 1/4 | 6.35 | 3/4 | 19.05 |
| 5/16 | 7.94 | 7/8 | 22.23 |
| 3/8 | 9.53 | 1 | 25.40 |
| 7/16 | 11.11 | ||
| 1/2 | 12.70 |
Fraction inches to decimal inches (and back)
When a plan says 3 3/8 in and your tool wants 3.375, the bridge is simple division: the fraction's top ÷ bottom. 3/8 = 0.375, so 3 3/8 in = 3.375 in. In reverse, multiply the decimal part by 16 and round: 0.375 × 16 = 6, so 0.375 in = 6/16 = 3/8 in. Sixteenths cover tape-measure work; for finer machining decimals, keep more digits — 0.3937 in is exactly 10 mm, and rounding it to 0.39 throws away real precision. Any fraction-to-length job is also where a dedicated length converter earns its keep: type the mixed number once instead of dividing by hand.
The formulas, all in one place
- cm → inches: divide by 2.54. Inches → cm: multiply by 2.54.
- Feet → metres: multiply by 0.3048. Metres → feet: divide by 0.3048 (or multiply by 3.2808).
- Yards → metres: multiply by 0.9144. Miles → km: multiply by 1.6093. Km → miles: multiply by 0.6214.
- Feet & inches → cm: (feet × 12 + inches) × 2.54. So 5 ft 9 in = 69 in × 2.54 = 175.26 cm.
Frequently asked questions
How tall is 170 cm in feet and inches?
170 cm is 5 feet 6.9 inches — usually rounded and spoken as 5'7". The maths: 170 ÷ 2.54 = 66.93 inches total, which is 5 full feet (60 inches) plus 6.93 inches.
How many centimetres is 5 foot 9?
5 foot 9 is 175.26 cm. There are 69 inches in 5 ft 9 (5 × 12 + 9), and each inch is exactly 2.54 cm, so 69 × 2.54 = 175.26 cm.
How do I convert mm to inches?
Divide the millimetres by 25.4. For example, 10 mm ÷ 25.4 = 0.3937 inches, and 50 mm ÷ 25.4 = 1.9685 inches. To go from inches to mm, multiply by 25.4 instead.
What is 3/8 of an inch in mm?
3/8 of an inch is 9.53 mm. As a decimal, 3/8 = 0.375 inches, and 0.375 × 25.4 = 9.525 mm, which rounds to 9.53 mm.
How long is 2 metres in feet?
2 metres is 6.56 feet — 6 feet 6.7 inches. One metre is 3.2808 feet, so multiply: 2 × 3.2808 = 6.5617 feet.
Why is an inch exactly 2.54 cm?
Since the international yard and pound agreement of 1959, the inch has been defined as exactly 25.4 millimetres. That makes every inch–metric conversion exact by definition rather than measured, which is why 25.4 appears in all the formulas on this page.
Convert anything the charts miss
The converter covers every unit pair — and the weight charts are the companion page for mass.