Cubic feet to cubic yards (cu ft to cu yd)

One cubic foot is exactly 0.037037037 cubic yards. 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: 50 cu ft x 0.037037037 = 1.85185 cu yd.

Going the other way, one cubic yard is 27 cubic feet.

To convert without a calculator, multiply by 0.03704. Rounding that to 0.037 is within 0.1% for most purposes.

Twenty-seven cubic feet to a cubic yard, because a yard is three feet and three cubed is 27. Forgetting that volume conversions cube the length factor (using 3 instead of 27) is the standard error in a concrete or gravel order.

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