One foot is exactly 304.8 millimeters. Multiply feet by 304.8. So 3.5 ft is 1,066.8 mm and 2.5 ft is 762 mm.
Where 304.8 comes from
Since the international yard and pound agreement of 1959, the inch has been defined as exactly 25.4 mm. A foot is 12 inches, so 12 × 25.4 = 304.8 mm exactly. Nothing is measured and nothing is approximated — the number is a consequence of the definition, which is why it terminates so neatly.
Common values
| Feet | Millimeters | Also |
|---|---|---|
| 0.5 ft | 152.4 mm | 6 in |
| 1 ft | 304.8 mm | 30.48 cm |
| 2 ft | 609.6 mm | 61 cm |
| 2.5 ft | 762 mm | 76.2 cm |
| 3 ft | 914.4 mm | 1 yard |
| 3.5 ft | 1,066.8 mm | 1.07 m |
| 4 ft | 1,219.2 mm | 1.22 m |
| 4.5 ft | 1,371.6 mm | 1.37 m |
| 5 ft | 1,524 mm | 1.52 m |
| 6 ft | 1,828.8 mm | 1.83 m |
| 10 ft | 3,048 mm | 3.05 m |
Why this conversion comes up
Almost always because a design specified in imperial has to be built with metric materials, or the reverse. Sheet goods, timber lengths and fixings are sold in millimeters across most of the world, while plans and habits in the US and parts of the UK are still in feet.
Two figures worth memorising for this: 1 ft = 304.8 mm and 8 ft = 2,438.4 mm, the latter because it is the standard sheet length that has to fit a metric space.
Common mistake
Rounding 304.8 to 300. It looks harmless and is a 1.6% error — about 48 mm lost over ten feet, which is more than enough to leave a visible gap. Keep the exact figure and round only the final answer.
One foot is 304.8 mm exactly (12 inches × 25.4 mm). Feet to millimeters comes up whenever imperial plans, timber sizes or US product specs have to be built or machined in a metric workshop.
Where you'll meet this conversion
- An 8 ft ceiling is 2,438 mm; a 6 ft 6 in door is 1,981 mm.
- A 4 × 8 ft sheet is 1,219 × 2,438 mm — which is why the metric board is 1,220 × 2,440.
- A 3.5 ft (42 in) counter height is 1,067 mm.
Common mistake
Entering feet-and-inches as a decimal: 5 ft 6 in is 5.5 ft, not 5.6 ft. Convert the inches first (6 ÷ 12 = 0.5) or convert feet and inches separately and add.
Quick answer: one foot equals 304.8 millimeters. So to convert feet to millimeters, multiply by 304.8.
How to convert feet to millimeters
millimeters = feet × 304.8
The foot (12 inches, exactly 0.3048 meters) remains the standard unit for human height and aviation altitude — even airlines in fully metric countries fly at "35,000 feet".
The millimeter is one thousandth of a meter and the workhorse of precision measurement — engineering drawings, 3D printing tolerances and rainfall totals are all quoted in millimeters.
Foot to Millimeter conversion table
| Foot (ft) | Millimeter (mm) |
|---|---|
| 0.01 ft | 3.048 mm |
| 0.1 ft | 30.48 mm |
| 0.25 ft | 76.2 mm |
| 0.4 ft | 121.92 mm |
| 0.75 ft | 228.6 mm |
| 1.25 ft | 381 mm |
| 1.75 ft | 533.4 mm |
| 2.5 ft | 762 mm |
| 3.5 ft | 1,066.8 mm |
| 4.5 ft | 1,371.6 mm |
| 6 ft | 1,828.8 mm |
| 8 ft | 2,438.4 mm |
| 10 ft | 3,048 mm |
| 12 ft | 3,657.6 mm |
| 14 ft | 4,267.2 mm |
| 16 ft | 4,876.8 mm |
| 18 ft | 5,486.4 mm |
| 20 ft | 6,096 mm |
| 24 ft | 7,315.2 mm |
| 26 ft | 7,924.8 mm |
| 30 ft | 9,144 mm |
| 35 ft | 10,668 mm |
| 45 ft | 13,716 mm |
| 55 ft | 16,764 mm |
| 65 ft | 19,812 mm |
| 75 ft | 22,860 mm |
| 85 ft | 25,908 mm |
| 95 ft | 28,956 mm |
| 110 ft | 33,528 mm |
| 125 ft | 38,100 mm |
| 175 ft | 53,340 mm |
| 250 ft | 76,200 mm |
| 350 ft | 106,680 mm |
| 450 ft | 137,160 mm |
| 600 ft | 182,880 mm |
| 750 ft | 228,600 mm |
| 900 ft | 274,320 mm |
| 1,500 ft | 457,200 mm |
| 2,500 ft | 762,000 mm |
| 10,000 ft | 3,048,000 mm |
Need the opposite direction? Use the Millimeter to Foot converter, or read our complete guide to length conversions for every formula in one place.
Frequently asked questions
How many millimeters are in one foot?
One foot equals 304.8 millimeters. Multiply any foot value by 304.8 to get millimeters.
What is 10 feet in millimeters?
10 feet equal 3,048 millimeters (10 × 304.8).
Is the foot to millimeter conversion exact?
The conversion factor used here (304.8) is based on the internationally agreed definitions of both units, so results are exact up to rounding of the final decimal places.
Is my data stored when I use this converter?
No. The conversion runs entirely in your browser with JavaScript — nothing you type is sent to a server, logged or stored.