To convert cups to tablespoons (cup to tbsp), multiply by 16. 1 cup equals 16 tbsp, about 67% of a soft-drink can.
| cups | tablespoons |
|---|---|
| 1 cup | 16 tbsp |
| 2 cups | 32 tbsp |
| 5 cups | 80 tbsp |
| 10 cups | 160 tbsp |
| 25 cups | 400 tbsp |
| 50 cups | 800 tbsp |
| 100 cups | 1,600 tbsp |
| 250 cups | 4,000 tbsp |
| 500 cups | 8,000 tbsp |
| 1000 cups | 16,000 tbsp |
The factor is 16.0000, which is derived rather than defined, so any decimal you see has been rounded somewhere.
For mental arithmetic the factor is close enough to 16 to use directly: multiply cups by 16 and the answer is right to within a rounding error.
The reverse factor is 0.063, so one tablespoon is that many cups. Two decimal places is plenty for most purposes, and three is more than a tape measure can justify.
To anchor the scale: 1 cup is about 16 tbsp.