fractions · cups · conversions
1/3 Cup, 3/4 Cup, and Other Fraction Conversions Explained
Why 1/3 cup isn't a whole number of tablespoons, how to measure it exactly using teaspoons, and a full table of every cup fraction you'll meet.
By Ali RazaUpdated 6 min read
A US cup holds exactly 16 tablespoons. That makes halves and quarters easy — 8 and 4 respectively — and thirds genuinely annoying, because 16 does not divide by 3.
There is a clean solution, and it is teaspoons.
The teaspoon rescue
There are 3 teaspoons in a tablespoon, and 48 in a cup. Since 48 divides evenly by 3, every cup fraction that is awkward in tablespoons becomes exact in teaspoons.
| Cups | Tablespoons | Measure it as | Teaspoons |
|---|---|---|---|
| ⅛ cup | 2 | 2 tbsp | 6 |
| ¼ cup | 4 | 4 tbsp | 12 |
| ⅓ cup | 5⅓ | 5 tbsp + 1 tsp | 16 |
| ⅜ cup | 6 | 6 tbsp | 18 |
| ½ cup | 8 | 8 tbsp | 24 |
| ⅝ cup | 10 | 10 tbsp | 30 |
| ⅔ cup | 10⅔ | 10 tbsp + 2 tsp | 32 |
| ¾ cup | 12 | 12 tbsp | 36 |
| ⅞ cup | 14 | 14 tbsp | 42 |
| 1 cup | 16 | 16 tbsp | 48 |
Why measuring 5 tablespoons and stopping is wrong
The missing third of a tablespoon is a full teaspoon — about 6% of the total. For flour that will not matter. For baking powder it absolutely will: a third of a tablespoon of leavening is a meaningful amount, and skipping it changes the rise.
Mixed fractions
| Cups | Tablespoons | Measure it as |
|---|---|---|
| 1¼ cups | 20 | 1 cup + 4 tbsp |
| 1⅓ cups | 21⅓ | 1 cup + 5 tbsp + 1 tsp |
| 1½ cups | 24 | 1 cup + 8 tbsp |
| 1⅔ cups | 26⅔ | 1 cup + 10 tbsp + 2 tsp |
| 1¾ cups | 28 | 1 cup + 12 tbsp |
| 2½ cups | 40 | 2 cups + 8 tbsp |
Going the other way: tablespoons to cups
Divide by 16. Some results are cleaner than others.
| Tablespoons | Cups | Easiest to measure as |
|---|---|---|
| 2 tbsp | ⅛ cup | 2 tbsp |
| 4 tbsp | ¼ cup | ¼ cup |
| 5 tbsp | 0.31 cup | 5 tbsp |
| 6 tbsp | ⅜ cup | ¼ cup + 2 tbsp |
| 8 tbsp | ½ cup | ½ cup |
| 10 tbsp | ⅝ cup | ½ cup + 2 tbsp |
| 12 tbsp | ¾ cup | ¾ cup |
| 14 tbsp | ⅞ cup | ¾ cup + 2 tbsp |
| 16 tbsp | 1 cup | 1 cup |
Halving and thirding recipes
Scaling is where fractions get unpleasant, and converting to tablespoons first makes it tractable.
- Half of ⅓ cup: 5⅓ tbsp ÷ 2 = 2⅔ tbsp = 2 tbsp + 2 tsp.
- Half of ¾ cup: 12 tbsp ÷ 2 = 6 tbsp = ¼ cup + 2 tbsp.
- A third of 1 cup: 16 tbsp ÷ 3 = 5⅓ tbsp = ⅓ cup. (Which is reassuring.)
- Half of ⅔ cup: 10⅔ tbsp ÷ 2 = 5⅓ tbsp = ⅓ cup.
For anything messier, convert to grams, halve the number, and convert back. Arithmetic on 133 g is easier than on ⅔ of a cup.
A note on the ingredient
Everything on this page is volume-to-volume, so none of it depends on what you are measuring. 16 tablespoons fill a cup whether it holds flour, honey or water. Only weight conversions care about the ingredient — which is why cup-to-tablespoon is the one conversion in baking you can safely memorise as a single number.