Convert cups to tablespoons (cup to tbsp)

One US cup is exactly 16 US tablespoons. 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: 0.5 cup x 16 = 8 tbsp.

Going the other way, one US tablespoon is 0.0625 US cups.

For mental arithmetic: Multiply by 16.

Sixteen tablespoons to the cup, which falls out of the chain rather than being defined: a cup is 8 fluid ounces, a fluid ounce is 2 tablespoons. The quarters are what people need, and they all land clean: a quarter cup is 4 tablespoons, a third is 5 and a third, a half is 8, three quarters is 12. The awkward one is the third, and it is the reason recipes scaled by thirds end up with 'five tablespoons plus one teaspoon' instructions: that is exactly a third of a cup.

Precision is worth matching to the input. A measurement given as 0.125 cup carries one or two significant figures, and reporting its conversion to six implies a precision the original never had.