The formula
ft = m × 3.280839895
Where the factor comes from — each unit by its definition, then its size in SI:
1 m is the SI unit of length.1 ft = 12 × in = 0.3048 m
Dividing the two SI sizes gives the factor: 3.28083989501 (rounded for display; the underlying ratio is fixed by the definitions). The reverse factor is 0.3048.
Every formula on this site takes lengths in metres. Heights, distances and stopping distances quoted in feet, inches or miles have to be converted first — getting it wrong by a factor of 3.28 is the most common unit slip in homework.
Worked examples
- A sprint track straight: 100 m = 328.084 ft — 100 × 3.280839895 = 328.084
- A marathon (42.195 km): 42,195 m = 138,435 ft — 42,195 × 3.280839895 = 138,435
- A tall doorway: 1.8288 m = 6 ft — 1.8288 × 3.280839895 = 6
- A school ruler (30 cm): 0.3 m = 0.984252 ft — 0.3 × 3.280839895 = 0.984252
Frequently asked questions
How many feet is 1 m?
1 m = 3.28083989501 ft.
How do I convert feet back to metres?
Divide by 3.28083989501 — or multiply by 0.3048: 1 ft = 0.3048 m.