ft US customary / imperial
Measures: Length — how far or how big
Foot
Twelve inches; the US everyday length.
LengthHow it's defined
Defined as exactly 0.3048 metres (12 inches of 25.4 mm each), fixed in 1959.
1 ft = 12 in = 0.3048 m — exact
Convert — honestly
ft equals
0.3048 m
Metre · factor exact — the base unit itself
12 in
Inch · factor exact — exact by the 1959 yard-and-pound agreement
0.000189393939 mi
Mile · factor exact — exact by definition
Conversions run through the metre using the stated factors — no rounding beyond display precision, and every factor says whether it's exact or measured.
Where you meet it
- Aviation altitude worldwide is measured in feet
- US room sizes and heights
Source
This page is an authored summary of the authoritative definition — checkable one click away.
NIST Special Publication 811 — Guide for the Use of the SI