The calculation
PantryGauge uses 120 g per US cup for the flour reference. One US cup contains 16 level tablespoons, so the derived result is 100 ÷ (120 ÷ 16) = 13.3 tablespoons.
Published calculators can show lower or higher results when they use a different flour weight, a different tablespoon volume, or a scooped/compacted method. The method belongs next to the number.
Level, heaped, or scooped
Fill each tablespoon lightly and sweep the top level. Do not dip the spoon into a packed flour bag and do not call a heaped spoon a level spoon. Those actions change the mass while the written tablespoon count stays the same.
If the recipe is sensitive to hydration or structure, put the bowl on a scale and add 100 g instead of trying to reproduce a volume estimate.
Regional tablespoons
This answer uses a US tablespoon convention. Metric tablespoon references are commonly 15 mL, while some Australian charts use 20 mL. A regional tablespoon can produce a different flour result, so identify the recipe's country when precision matters.
Questions readers ask
How many tablespoons is 100 g of plain flour?
Using 120 g per US cup and 16 level US tablespoons per cup, 100 g is about 13.3 level tablespoons.
Can I round 100 g flour to 13 tablespoons?
Yes, as a practical kitchen estimate, but the result will not be as repeatable as weighing 100 g.
Is plain flour the same as all-purpose flour?
In many recipes they are close naming equivalents, but milling, brand, and regional convention can differ. Use the flour named by the recipe.
Why do online answers show different tablespoon counts?
They may use different grams-per-cup values, spoon sizes, or filling methods such as levelled versus scooped flour.
Sources and method
Numerical answers are tied to the stated ingredient, state, cup convention, and source. Derived values are calculated from the cited reference and rounded for kitchen use.