Feet to Millimeters
An instant feet-to-millimeters converter, with the formula and a reference table below.
| Feet | Millimeters |
|---|---|
| 1 ft | 304.8 mm |
| 2 ft | 609.6 mm |
| 3 ft | 914.4 mm |
| 5 ft | 1524 mm |
| 10 ft | 3048 mm |
| 25 ft | 7620 mm |
| 50 ft | 15240 mm |
| 100 ft | 30480 mm |
How to use
- Enter a value in the Feet field.
- The Millimeters figure appears immediately — no button to press.
- Typing in the Millimeters field converts back to Feet the same way.
- Use the reference table for the values that come up most often.
Feet to Millimeters formula
To convert feet to millimeters, multiply by 304.8.
mm = ft × 304.8
Why this factor: the foot and the millimeter are both defined against the meter, so dividing one definition by the other gives 304.8 directly. Both definitions are set out in full below.
To go the other way, divide by 304.8 — or use the Millimeters to Feet converter, which is the same calculation reversed.
Worked example
Given 12 ft, multiplying by 304.8 yields 3657.6 mm.
12 ft × 304.8 = 3657.6 mm
The converter above does this for any value you type, in either direction.
What is a foot?
A foot is twelve inches, the primary unit for human-scale dimensions in the US.
Definition: Exactly 0.3048 meter since 1959 — one third of the international yard.
Where it is used: Building heights, room dimensions, aviation altitude worldwide, and personal height in the US and UK.
Worth knowing: The US survey foot, very slightly longer, was used in land surveying until it was officially retired at the end of 2022.
What is a millimeter?
A millimeter is one thousandth of a meter — the working precision unit of manufacturing and construction.
Definition: Exactly 0.001 meter by SI prefix definition.
Where it is used: Engineering drawings, machining tolerances, timber and steel dimensions, rainfall totals.
Feet vs Millimeters
The foot is an imperial unit while the millimeter is a metric unit. That is why the factor between them is not a round number: the two systems were defined independently and only later tied together by exact agreement.
Frequently asked questions
How many millimeters are in a foot?
One foot equals 304.8 millimeters.
What is the formula to convert feet to millimeters?
Multiply the number of feet by 304.8. To reverse it, divide by 304.8 instead.
How do I convert millimeters back to feet?
Divide by 304.8, which is the same as multiplying by 0.0032808399.
How many millimeters are in 10 feet?
10 ft works out to 3048 mm.
Is there anything to watch out for with feet?
The US survey foot, very slightly longer, was used in land surveying until it was officially retired at the end of 2022.
How is the foot defined?
Exactly 0.3048 meter since 1959 — one third of the international yard.