Feet to Millimeters (ft → mm) – Exact Conversion Guide
Core idea: 1 foot = 0.3048 m exactly and 1 m = 1000 mm ⇒ 1 foot = 304.8 mm (exact). Multiply feet by 304.8 to get millimeters. Reverse: divide mm by 304.8.
Formulas
mm = ft × 304.8ft = mm ÷ 304.8- Via inches (optional):
mm = ft × 12 × 25.4 (since 1 in = 25.4 mm).
Quick Values
| Feet | Millimeters | Centimeters |
|---|
| 0.5 | 152.4 | 15.24 |
| 1 | 304.8 | 30.48 |
| 5 | 1524 | 152.4 |
| 6 | 1828.8 | 182.88 |
| 10 | 3048 | 304.8 |
| 25 | 7620 | 762 |
Worked Example
Example: Convert 6 ft to mm.
mm = 6 × 304.8 = 1828.8 mm (exact to one decimal because factor exact).
Where Used
- Precision fabrication drawings requiring mm output.
- 3D printing adaptation from imperial measurements.
- Interior design / cabinetry specs (hardware hole spacing).
- Scientific instrument mounting dimensions.
Accuracy & Tips
- 304.8 is exact—no cumulative error from chaining conversions.
- Fast mental approximation: feet × 300 gives a quick lower value; add 1.6% to reach the exact mm.
- Feet + inches:
mm = (ft × 12 + in) × 25.4.
- Reverse quick: mm ÷ 300 ≈ ft (slightly high), subtract ~1.6% for better accuracy.
More Examples
| Feet (ft) | Millimeters (mm) | Meters (m) |
|---|
| 2 | 609.6 | 0.6096 |
| 8 | 2438.4 | 2.4384 |
| 12 | 3657.6 | 3.6576 |
| 15 | 4572 | 4.572 |
| 30 | 9144 | 9.144 |
FAQ
- Is 304.8 mm exact? Yes—defined through the exact inch (25.4 mm) and 12 inches per foot.
- How many feet is 1000 mm? 1000 ÷ 304.8 ≈ 3.28084 ft.
- Convert 1829 mm to feet & inches: 1829 ÷ 304.8 ≈ 6.0007 ft → ≈ 6 ft 0.008 in (practically 6 ft).
- Which is bigger: 1 m or 3 ft? 1 m (1000 mm) vs 3 ft (914.4 mm) → 1 m is longer.
All figures based on exact SI relationships; rounding only for display.