A foot is exactly 0.3048 meters.
Feet to Millimeters Converter — ft to mm
Convert Foot (ft) to Millimeter (mm) using the exact conversion factor (1 foot = 304.8 millimeter). See the formula, worked examples, conversion table, unit comparison, history, and common uses.
Feet to Millimeters converter
Converter
Length Converter
Convert SI, imperial, US customary, astronomical, scientific, and historical length units.
Context values
Some unit families need one extra value for a physically accurate result.
Millimeter is 0.001 meter units.
Result = input x 0.3048 / 0.001.
Length uses the meter as the base unit.
Reserved above the conversion cards and below the converter.
About Converting Feet to Millimeters
Foot and Millimeter both measure length. Foot is typically associated with united States (height, construction, aviation altitude), while Millimeter is typically associated with standard small/precision length unit worldwide, including in US engineering and manufacturing.
Formula
millimeters = feet × 304.8
This factor comes from each unit's defined relationship to the category's base unit: 1 foot equals 0.3048 base units, and 1 millimeter equals 0.001 base units, so dividing one by the other gives the direct foot-to-millimeter factor of 304.8.
Simple example
1 ft × 304.8 = 304.8 mm
1 foot = 304.8 millimeters.
Real-world example
10 ft × 304.8 = 3,048 mm
10 feet = 3,048 millimeters.
Conversion table
| Foot (ft) | Millimeter (mm) |
|---|---|
| 1 ft | 304.8 mm |
| 5 ft | 1,524 mm |
| 10 ft | 3,048 mm |
| 21.0975 ft | 6,430.518 mm |
| 42.195 ft | 12,861.036 mm |
| 100 ft | 30,480 mm |
Reverse conversion: Millimeter to Foot
304.8 mm × 0.003280839895 = 1 ft
304.8 millimeters = 1 foot.
feet = millimeters × 0.00328083989501
For a page dedicated to this direction, see Millimeter to Foot.
Foot vs. Millimeter
| Aspect | Foot | Millimeter |
|---|---|---|
| Family | US/imperial customary unit | SI derived (metric prefix) unit |
| Typical use | Height measurement in the US and UK | Engineering drawings and manufacturing tolerances worldwide (including in the US) |
| Where it's used | United States (height, construction, aviation altitude) | Standard small/precision length unit worldwide, including in US engineering and manufacturing |
Understanding the Foot
Foot (ft) measures distance. The international foot is defined as exactly 0.3048 meters. It is classified as a US/imperial customary unit.
Where it's used: United States (height, construction, aviation altitude) United Kingdom (height, some construction contexts)
Uses of the Foot today
- Height measurement in the US and UK
- US construction and real estate (square footage)
- Aviation altitude worldwide (feet remain standard even in metric countries)
History of the Foot
The foot has ancient roots (Roman 'pes', various regional English feet), standardized into the modern English foot over centuries. The international foot (exactly 0.3048 m) was fixed by the 1959 International Yard and Pound Agreement, resolving small historical differences between US and UK measurements.
Historical origin. Foot was not the invention of a single named person; it developed through the process described above.
Understanding the Millimeter
Millimeter (mm) measures distance. A millimeter is one-thousandth of a meter. It is classified as a SI derived (metric prefix) unit.
Where it's used: Standard small/precision length unit worldwide, including in US engineering and manufacturing
Uses of the Millimeter today
- Engineering drawings and manufacturing tolerances worldwide (including in the US)
- Rainfall measurement in most countries
- Small-scale everyday measurement (screen sizes, hardware)
History of the Millimeter
The millimeter follows from the meter via the 'milli-' SI prefix (10⁻³). It is notable as one of the few metric units in routine US technical/engineering use, since precision manufacturing and electronics are often specified in millimeters even in the US.
Historical origin. Millimeter was not the invention of a single named person; it developed through the process described above.
Foot — sources
- NIST — International yard and pound (1959) — Fixes the modern foot at exactly 0.3048 meters.
Millimeter — sources
- BIPM SI Brochure — SI prefixes — Defines 'milli-' as the prefix for 10⁻³.
Reserved between the cards and the FAQ so the page stays balanced.
Frequently asked questions
How many millimeters are in 1 foot?
1 foot equals 304.8 millimeters, using the exact defined conversion factor rather than an estimate.
How do I convert foot to millimeter?
Multiply the foot value by 304.8. The converter above does this instantly to whatever precision you set.
How do I convert millimeter back to foot?
Use the reverse factor: 1 millimeter equals 0.0032808399 feet. You can also use the swap control in the converter above to flip the direction instantly.
What is a foot?
Foot (ft) measures distance. The international foot is defined as exactly 0.3048 meters. It is classified as a US/imperial customary unit.
What is a millimeter?
Millimeter (mm) measures distance. A millimeter is one-thousandth of a meter. It is classified as a SI derived (metric prefix) unit.
Is the foot to millimeter conversion exact?
Yes. The international foot is defined as exactly 0.3048 meters. That fixed definition is what the converter above uses, so any rounding you see is a display choice, not a limitation of the math.
Where is the foot still used today?
United States (height, construction, aviation altitude) United Kingdom (height, some construction contexts)