Why one tablespoon is not one number

A US tablespoon is 14.78676478125 millilitres. That part is fixed by law and never changes. What changes is how much mass fits in those millilitres.

Water fills them with 14.8 grams. Honey fills the same space with 21 grams, because honey is denser than water. A tablespoon of cocoa powder holds 5.4 grams, because cocoa is mostly air between fine particles.

So the question "how many grams in a tablespoon" has 30 answers in the table below, and the only way to pick the right one is to name the ingredient.

Where the 15 gram rule comes from, and where it breaks

Water is 14.79 grams a tablespoon, and a lot of people round that to 15. Nutrition labels lean on the same shortcut, since a tablespoon is defined as 15 millilitres for labelling purposes in the US.

For baking it is a trap. A tablespoon of flour is 7.5 grams, so using 15 overstates it by 100 percent. A tablespoon of honey at 21 grams means the shortcut understates it by nearly 30 percent. Either way your recipe notices.

One tablespoon of each ingredient, in grams

Every figure below is the ingredient density in grams per cup divided by 16, the number of tablespoons in a US customary cup. The densities are the same vetted set the cups to grams converter uses.

Ingredient	1 tbsp, g	1 tbsp, oz	1 tsp, g	1/2 cup, g
Shredded Coconut	5.3	0.19	1.8	42.5
Cocoa Powder	5.4	0.19	1.8	43
Rolled Oats	5.6	0.2	1.9	45
Almonds (sliced)	5.8	0.2	1.9	46
Almond Flour	6	0.21	2	48
Cake Flour	7.1	0.25	2.4	57
All-Purpose Flour	7.5	0.26	2.5	60
Whole Wheat Flour	7.5	0.26	2.5	60
Powdered Sugar	7.5	0.26	2.5	60
Coconut Flour	7.5	0.26	2.5	60
Bread Flour	7.9	0.28	2.6	63.5
Cornstarch	8	0.28	2.7	64
Cornmeal	9.4	0.33	3.1	75
Raisins	10.3	0.36	3.4	82.5
Semolina	10.4	0.37	3.5	83.5
Chocolate Chips	10.6	0.37	3.5	85
White Rice (uncooked)	11.6	0.41	3.9	92.5
Brown Rice (uncooked)	11.9	0.42	4	95
Granulated Sugar	12.5	0.44	4.2	100
Vegetable Oil	13.6	0.48	4.5	109
Brown Sugar (packed)	13.8	0.49	4.6	110
Butter	14.2	0.5	4.7	113.5
Water	14.8	0.52	4.9	118.5
Table Salt	18	0.63	6	144
Baking Powder	14.4	0.51	4.8	115
Maple Syrup	19.5	0.69	6.5	156
Honey	21.3	0.75	7.1	170

Sorted lightest to heaviest. The teaspoon column is one third of the tablespoon column, and the half cup column is eight tablespoons. Both come out of the same density, so the table cannot contradict the tool above.

Common amounts in grams, four ingredients

The same fractions, worked out for the four ingredients people convert most.

Tablespoons	Butter, g	Flour, g	Sugar, g	Honey, g
1/2 tbsp	7.1	3.8	6.3	10.7
1 tbsp	14.2	7.5	12.5	21.3
2 tbsp	28.4	15	25	42.5
3 tbsp	42.6	22.5	37.5	63.8
4 tbsp	56.8	30	50	85
8 tbsp	113.5	60	100	170
16 tbsp	227	120	200	340

Note the eight tablespoon row. Half a cup of butter is 113.5 grams, and half a cup of flour is 60 grams. Same eight spoons, nearly double the weight.

Spoon sizes around the world

Tablespoon is not one volume either. The common standards sit within about 5 percent of each other, which is small next to the ingredient spread but not zero.

Standard	Millilitres	Where you meet it
US customary tablespoon	14.7868	American recipes and measuring spoons
US legal tablespoon	15.0	Nutrition labels
Metric tablespoon	15.0	Australia and New Zealand
UK tablespoon	15.0	Most modern British recipes
Australian tablespoon	20.0	Australian recipes, four teaspoons

The tool above uses the US customary tablespoon, 14.78676478125 millilitres, because that is what the densities were measured against. If a recipe is Australian it may mean 20 millilitres, which is 35 percent more volume and 35 percent more weight.

Worth flagging, because Australian tablespoons are four teaspoons rather than three. That single extra teaspoon quietly changes every spoon measurement in the recipe.

Questions cooks actually ask

How many grams is a tablespoon of butter?: About 14.2 grams, and most recipes call it 14. An American stick of butter is 113 grams, which is 8 tablespoons, so the arithmetic checks out cleanly if you treat each tablespoon as 14.2.
Is a tablespoon always 15 grams?: Only for water, and only because the millilitres happen to weigh close to the millilitre count. Flour is 7.5 grams a tablespoon. Honey is 21.3. The 15 gram rule is a water rule wearing a general purpose hat.
How many tablespoons are in 100 grams of flour?: About 13.3 tablespoons, since a tablespoon of all-purpose flour is 7.5 grams. That is a little over three quarters of a cup, which is 12 tablespoons. So weigh it if the recipe is fussy, because fourteen spoonfuls of scooped flour can run closer to 120 grams.
Why does my tablespoon of flour weigh more than the table says?: Because of how you filled the spoon. Dipping the spoon into the bag compacts the flour, and a dipped tablespoon can weigh 9 or 10 grams instead of 7.5. Spooning flour into the spoon and levelling it off gets closer to the published number.
Does a tablespoon of honey really weigh 21 grams?: Yes, and it varies with water content. Honey is hygroscopic and picks up moisture from the air, so an old jar runs slightly lighter than one opened fresh. The range is roughly 20 to 21.5 grams a tablespoon.
Should I use a scale instead of spoons?: For baking, yes. A scale removes the fill method from the equation entirely, and a gram is a gram no matter who holds the scoop. For a splash of vanilla or a pinch of salt, spoons are fine and faster.

Where these numbers come from

The US customary tablespoon is defined as half a fluid ounce, and a fluid ounce as 29.5735295625 millilitres, so a tablespoon is exactly 14.78676478125 millilitres. That is a definition, not a measurement, so it carries no error.

The per ingredient weights come from the density set this site maintains, published in full on the cups to grams page with the sourcing and method for each figure. Every weight here is that density divided by 16, computed in code rather than typed, so the table and the tool cannot disagree. That is also why 1 cup of flour shows as 16 tablespoons of 7.5 grams and lands on 120 grams exactly.

Flour is the one worth a caveat, and the sources genuinely disagree. This site uses 120 grams a cup. USDA FoodData Central lists white all-purpose flour at 125 grams a cup, which works out nearer 7.8 grams a tablespoon. Food Standards Australia New Zealand publishes a plain flour density close to 128 grams a cup. The spread is real and comes from how the cup and spoon were filled, so weigh it when the recipe is fussy.

Related converters

These run on the same density set.

Tablespoons to Grams.