Feet Converter

Article — Feet Converter

Feet converter: ft to meters, centimeters, inches, yards, miles

The feet converter swaps feet between metres, centimeters, inches, yards, miles, millimeters, and kilometers. Every conversion runs through the exact factor 1 ft = 0.3048 m, set by the 1959 International Yard and Pound Agreement and used in every English-speaking country since. Outputs include a feet-and-inches breakdown so you can read body height as 5′9″ rather than 1.7526 m.

The foot is the workhorse unit of US construction, aviation altitudes, and English-speaking everyday measurement. Despite the metric world’s overwhelming preference for meters, the foot is not going anywhere: ICAO uses feet for flight levels globally, American building codes use feet and inches, and the US construction industry runs on foot-and-inch math.

What the feet converter handles

The calculator accepts feet, metres, centimeters, millimeters, kilometers, inches, yards, and miles as input. The dropdown picks the source unit; the converter computes the metre-equivalent and divides by each target unit’s metre-equivalent to produce all outputs at once.

The headline auto-flips: feet input shows metres on top, metric input shows feet on top. When input is metric, an additional row shows the value as feet and inches (e.g. 1.75 m = 5′8.9″), useful for body height. Values below 0.0001 ft or above 100,000 ft switch to scientific notation.

Feet to meters: the master factor

The defining relationship: 1 ft = 0.3048 m exactly. From this single fact, every other feet conversion flows.

Before 1959, different countries used slightly different feet. The British imperial foot ran 0.30479997 m; the US survey foot was 0.30480061 m. The 1959 agreement — signed by the US, UK, Canada, Australia, New Zealand, and South Africa — set 1 ft = 0.3048 m exactly. The US kept a parallel survey foot for geodetic work until officially retiring it on 1 January 2023.

Feet and inches for body height

Americans, British people, and many post-imperial countries record body height in feet and inches. A typical adult man stands 5′9″ (175.3 cm); a typical adult woman stands 5′4″ (162.6 cm). To convert metres to feet-and-inches:

1. Multiply metres by 3.28084 to get total feet
2. Take the integer part as feet
3. Multiply the fractional part by 12 to get inches

Feet converter mental shortcuts

For approximate work, two shortcuts cover most cases:

• m to ft: multiply by 3.3 (error: +0.5%)
• ft to m: divide by 3.3 or multiply by 0.3 (error: −1.6%)
• m to ft & in: m × 3.3, take integer ft, mult fraction by 12
• cm to ft: divide by 30 (very rough), use 30.48 for accuracy
• ft to cm: ft × 30 + ft (e.g. 6 ft ≈ 180+6 = 186 cm; true: 182.9)
• Whole foot in cm: 1 ft ≈ 30 cm (within 1.6%)

For engineering work, always use the exact 0.3048 factor. For a 100-foot beam, the shortcut gives 30 m; the exact value is 30.48 m — a 1.6% error that matters in structural calculations.

Feet in aviation and construction

Two industries lock the foot into modern engineering practice.

Aviation uses feet for altitude worldwide. ICAO standard. Flight levels (FL) refer to standard-pressure altitude in hundreds of feet. FL350 = 35,000 ft, a typical cruise altitude for a 747. Vertical separation rules use feet too: RVSM (Reduced Vertical Separation Minimum) aircraft must hold within 200 ft of assigned altitude. Switching aviation to metric would require re-equipping millions of aircraft.

US construction runs on feet and inches. Stud spacing at 16″ on-centre, ceiling heights at 8′0″ or 9′0″, lumber in 2-by-4 nominal sizes, pipes in fractional-inch diameters. The construction industry uses feet because the rest of US infrastructure (zoning, drawings, materials) does.

International vs US survey foot

From 1893 until 2023 the US used two definitions of the foot.

The international foot: 1 ft = 0.3048 m exactly (1959 agreement, used by everyone else and by most US contexts).

The US survey foot: 1 ft = 1200/3937 m ≈ 0.30480061 m (used for geodetic and land-survey work). The difference is 2 parts per million — about 1 inch in 16 miles. Trivial for everyday use, significant for state-plane coordinate systems.

NIST officially deprecated the US survey foot on 1 January 2023, after a decade of notice. New surveys use the international foot; legacy data sets are preserved but no longer extended. The Federal Register notice walks through the transition rules for surveyors and engineers.

Common feet conversion mistakes

• Forgetting feet vs inches: 5′9 ft (wrong) vs 5′9″ (right)
• Mile = 5000 ft: it’s 5280 ft, from the 8-furlong definition
• Survey vs international foot: 2 ppm difference, big in large-area surveys
• Mixing yard and meter: 1 yd = 0.9144 m, NOT 1 m

Why the foot survives in a metric world

Almost every country has officially adopted the metric system. Yet the foot persists in three globally important domains: aviation, construction (US, UK, Canada), and human-body measurement (most English-speaking countries). The persistence is not mere stubbornness.

Aviation locks in the foot because international air-traffic control coordinates altitude in feet. Changing it would require simultaneous re-certification of every aircraft, every radar, and every controller globally — trillions of dollars and decades of risk. China and Russia officially use metres in their domestic airspace but still report flight levels in feet for international flights.

US construction runs on the foot because the entire supply chain — lumber, steel, drywall, fasteners, plumbing pipe, electrical conduit — is sized in inches and feet. Switching would require re-tooling every mill and revising every building code. The industry has voted with its inertia for several decades.