Baking powder references can differ by product and measuring convention. This entry keeps a King Arthur double-acting baking-powder source measure separate from a Dr. Oetker sachet reference.
Read the product-specific basis
The Dr. Oetker reference combines the manufacturer’s level-teaspoon description with the stated sachet quantity and a teaspoon-volume relationship from its recipe material.
That evidence supports the named product within the stated scope. It is not a universal bulk density for every baking powder. Keep the product reference visible when selecting it.
Preserve a source spoon
The King Arthur spoon remains a source measure where its millilitre definition is not established. It can scale within the original relationship without being relabeled as a defined physical teaspoon.
If your recipe already gives a mass, use it directly. A known sachet mass can also be treated as a mass amount when it is the amount actually called for.
Inspect a small result carefully
Choose a fraction or decimal display that preserves enough information for the scaled amount. Do not silently round a small nonzero result to zero.
Baking powder and baking soda remain separate ingredients. The converter does not establish a substitution between them or adjust the recipe’s other ingredients to compensate.