Ft to inches (ft to in)

One foot is exactly 12 inches. That ratio belongs to the customary system itself and is much older than any link to metric: the 1959 international yard and pound agreement later fixed the yard and the pound against the meter and the kilogram, but it left the ratios between customary units (feet to the yard, ounces to the pound, cups to the gallon) exactly as they were.

Worked through: 5 ft x 12 = 60 in.

Going the other way, one inch is 0.0833333333 feet.

To convert without a calculator, multiply by 12. Rounding that to 12 is within 1.5e-14% for most purposes.

Twelve inches to the foot, which is the only base-12 survivor in everyday measurement and the reason imperial arithmetic is awkward. It does divide neatly by 2, 3, 4 and 6, which is why it survived for carpentry.

Precision is worth matching to the input. A measurement given as 1 ft carries one or two significant figures, and reporting its conversion to six implies a precision the original never had.