Length

ft to mm conversion

Convert foot (ft) to millimetre (mm). Length units span pipe diameters (mm, inch), plant dimensions (m, ft), and roughness (µm) — mixing metric and imperial is routine.

1 ft = 304.8 mm

Formula

To convert foot to millimetre, multiply the ft value by 304.8. To go the other way, divide by 304.8 (or multiply by 0.00328084).

ft to mm conversion table

ftmm
1304.8
2609.6
51524
103048
257620
5015240
10030480
25076200
500152400
1000304800

Used in practice

Pipe sizes are labelled in inches (NPS) but calculated in mm; equipment layouts mix metres and feet.

Velocity scales with the inverse square of diameter, so a small length error compounds quickly in flow calculations.

Worked example. A length of 0.328084 ft is 100 mm.

Frequently asked questions

How do you convert foot to millimetre?

Multiply the value in ft by 304.8 to get mm. For example, 10 ft = 3048 mm.

What is 1 ft in mm?

1 ft equals 304.8 mm.

Where is this conversion used?

Pipe sizes are labelled in inches (NPS) but calculated in mm; equipment layouts mix metres and feet.

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