31 inches at a glance
- Centimeters
- 78.74 cm
- Millimeters
- 787.4 mm
- Meters
- 0.7874 m
- Feet & inches
- 2 ft 7 in
- Feet (decimal)
- 2.5833 ft
- Nearest whole cm
- 79 cm
How to convert 31 inches to cm
cm = inches × 2.54
31 × 2.54 = 78.74 cm
31 × 2.54 = 78.74 cm
Because the inch is defined as exactly 2.54 cm, 78.74 cm is exact — no rounding involved. To do it in your head, split 2.54 into 2.5 + 0.04: 31 × 2.5 = 77.5 and 31 × 0.04 = 1.24, which add up to 78.74.
Fractions of an inch around 31 in
Tape measures between 31 and 32 in are marked in eighths. Each eighth adds 3.175 mm:
| Inches | Centimeters | Millimeters |
|---|---|---|
| 31 | 78.74 | 787.4 |
| 31 1/8 | 79.0575 | 790.575 |
| 31 1/4 | 79.375 | 793.75 |
| 31 3/8 | 79.6925 | 796.925 |
| 31 1/2 | 80.01 | 800.1 |
| 31 5/8 | 80.3275 | 803.275 |
| 31 3/4 | 80.645 | 806.45 |
| 31 7/8 | 80.9625 | 809.625 |
31 inches in real life
- Screens. A 31-inch 16:9 screen (measured diagonally) is 78.7 cm across the diagonal, about 27.0 × 15.2 in (68.6 × 38.6 cm) for the picture itself.
- Clothing. US jeans and trousers are sized by waist and inseam in inches, so a 31 in waist is 78.7 cm around, and a 31 in inseam is 78.7 cm long.
Objects of a similar size
- 3% longer than the height of a typical desk or dining table, 76.2 cm (30 in).
- 5% longer than the circumference of a regulation basketball, 74.93 cm (29.5 in).
- 14% shorter than a yardstick, 91.44 cm (36 in).
Inches near 31 in
| Inches | Centimeters | Feet & inches / mm |
|---|---|---|
| 26 in | 66.04 cm | 2 ft 2 in |
| 27 in | 68.58 cm | 2 ft 3 in |
| 28 in | 71.12 cm | 2 ft 4 in |
| 29 in | 73.66 cm | 2 ft 5 in |
| 30 in | 76.2 cm | 2 ft 6 in |
| 31 in | 78.74 cm | 2 ft 7 in |
| 32 in | 81.28 cm | 2 ft 8 in |
| 33 in | 83.82 cm | 2 ft 9 in |
| 34 in | 86.36 cm | 2 ft 10 in |
| 35 in | 88.9 cm | 2 ft 11 in |
| 36 in | 91.44 cm | 3 ft |
Going the other way: 79 cm to inches is 31.10 in.
Frequently asked questions
How many cm is 31 inches?
31 inches is exactly 78.74 cm, because one inch is defined as 2.54 cm.
What is 31 inches in mm?
31 in = 787.4 mm (multiply by 25.4).
How many feet is 31 inches?
31 in is 2.5833 feet, or 2 ft 7 in.
Is 31 inches the same as 79 cm?
Not quite: 31 in is 78.74 cm, so 79 cm is 2.6 mm too long — close enough for most everyday measuring.