Length / ft → mm
Convert Feet to Millimeters
From a small measurement to a long distance. Move between metric and imperial units. Convert Feet (ft) to Millimeters (mm). Find the formula, worked examples, unit definitions, and practical guidance below.
Reverse: Millimeters to Feet →
How to convert feet to millimeters
Length conversion changes the unit of a distance. Area and volume need squared and cubed factors; this calculator does not convert square feet or cubic feet.
Use x for the value in ft, b for the intermediate value in m, and y for the result in mm.
mm = ft × 0.3048 ÷ 0.001
Worked examples
10 ft ≈ 3048 mm
Step 1: (10 × 0.3048) ≈ 3.048 m.
Step 2: 3.048 ÷ 0.001 ≈ 3048 mm.20 ft ≈ 6096 mm
Step 1: (20 × 0.3048) ≈ 6.096 m.
Step 2: 6.096 ÷ 0.001 ≈ 6096 mm.
Results are rounded to 12 significant digits. Converting units does not increase the precision of the original measurement. Very large or small values outside JavaScript’s finite numeric range are rejected.
About Feet
The international foot is exactly 0.3048 meters and contains 12 inches. Enter fractional feet as decimals, rather than treating inches as decimal digits.
About Millimeters
A millimeter is one thousandth of a meter. Small dimensions and engineering drawings often use millimeters; retain the precision of the original measurement.
Definitions and sources
Feet, inches, and the decimal in between
A measurement written as 6 feet 6 inches cannot be entered as 6.6 feet. Feet divide into 12 inches, while the digits after a decimal point describe tenths, hundredths, and so on.
Turn feet and inches into decimal feet
Divide the inches by 12, then add the whole feet:
Decimal feet = feet + inches ÷ 12
For 6 feet 6 inches, that gives 6 + 6 ÷ 12 = 6.5 feet. For 5 feet 9 inches, the result is 5.75 feet.
Enter this decimal value in the feet to meters converter. One international foot equals exactly 0.3048 meters, so 6.5 feet equals 1.9812 meters.
Turn decimal feet back into feet and inches
Keep the whole-number part as feet. Multiply the remaining fraction by 12 to get inches.
For 5.75 feet:
- Keep 5 as the number of feet.
- Take the fraction, 0.75.
- Multiply 0.75 × 12 = 9 inches.
The measurement is 5 feet 9 inches. If rounding the inches produces 12, carry that into the feet: 5 feet 12 inches becomes 6 feet.
Choose a useful level of precision
A calculator can display many digits, but a tape measure may only resolve a small fraction of an inch. Match the precision of your result to the purpose of your measurement.
For a precise calculation, keep the unrounded value until the final step. For a quick estimate of height, rounding to the nearest centimeter is often easier to read.
Need the other direction? Use meters to feet, or compare smaller measurements with inches to centimeters.
Use consistent length units when carrying dimensions into construction calculations.
Feet to millimeters reference table
| Feet (ft) | Millimeters (mm) |
|---|---|
| 1 | 304.8 |
| 5 | 1524 |
| 10 | 3048 |
| 25 | 7620 |
| 50 | 15240 |
| 100 | 30480 |
| 1000 | 304800 |
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