Yeast Conversion Calculator
Swap between fresh, active dry and instant yeast with the usual ratios when a recipe names a different type.
The conversion ratios
A widely used rule of thumb is 3 parts fresh yeast = 1.25 parts active dry = 1 part instant. So 9 g fresh yeast ≈ 3.75 g active dry ≈ 3 g instant.
Active dry yeast is often rehydrated in warm water first, while instant yeast can go straight into the flour. The amounts here are equivalents, not substitutions for the method.
How precise is it?
Brands differ in activity and moisture, and recipes with long cold fermentation tolerate small differences. Treat the result as a starting point and watch the dough rather than the clock.
FAQ
Is 3 : 1.25 : 1 exact?
No. It is a convention. Some sources use 2.5–3 for fresh yeast or 1.33 for active dry, so small differences are normal.
Do I need to change the water?
Fresh yeast adds a little moisture, but the effect is tiny for home recipes and the calculator does not adjust water.
Can I use this for sourdough starter?
No. A starter is a living culture, not a measured yeast amount. See the sourdough feeding calculator.
Other Languages
References
How we make sure
We check this tool with the automated test suites linked below. Example checks are shown in their original language.
- Verification method
- Check that 3 g instant equals 3.75 g active dry and 9 g fresh, that conversions round-trip, and that unknown yeast types are rejected.
- Comparison reference
- The conventional 3 : 1.25 : 1 equivalence; published sources disagree, so this is a fixed convention rather than an independently verified constant.
- Verification scope
- Only these samples and boundaries are checked; this does not prove correctness for every input or guarantee a bake.
Test source and cases (select a file to read it)
-
baker-tools.test.js
- yeast: 3 g instant equals 3.75 g active dry and 9 g fresh
- yeast: converting fresh to instant and back is stable
- yeast: unknown types and prototype keys are rejected
These checks cover the listed examples and boundaries, not every possible input. Round trips and checks using the same library are not independent verification.