Convert between fresh (cake), active dry and instant yeast. Enter an amount in grams, teaspoons, tablespoons, ounces or packets, choose what you have and what the recipe wants, and convert — using Red Star's published conversion ratios.
| Conversion | Ratio | Note |
|---|---|---|
| Active Dry ↔ Instant | 1 : 1 | Substitute directly, same weight or volume |
| Fresh → Active Dry | ×0.4 | Some recipes use a simpler ÷2 (×0.5) rule instead |
| Fresh → Instant | ×0.33 | — |
| Active Dry → Fresh | ×2.5 | Inverse of Fresh→Active Dry |
| Instant → Fresh | ×3.03 | Inverse of Fresh→Instant |
| Measure | Value |
|---|---|
| 1 standard packet (active dry / instant) | 7 g = 0.25 oz = 2¼ tsp |
| Active Dry / Instant, per teaspoon | ≈3 g/tsp |
| Fresh (cake) yeast, per teaspoon | ≈8 g/tsp |
| Fresh yeast | Active Dry equivalent | Instant equivalent |
|---|---|---|
| 15 g | 6.0 g (2 tsp) | 5.0 g (1.65 tsp) |
| 30 g | 12.0 g (4 tsp) | 9.9 g (3.3 tsp) |
| 45 g | 18.0 g (6 tsp) | 14.9 g (4.95 tsp) |
All three common baking yeasts — fresh (cake) yeast, active dry yeast, and instant yeast — are the same living organism (Saccharomyces cerevisiae) processed differently. Fresh yeast is sold as a moist, perishable block that's roughly 70% water, so gram-for-gram it contains far fewer active yeast cells than a dried product. Active dry yeast is dried into coarser granules with a protective outer layer of dead cells, which traditionally meant it needed to be dissolved ("proofed") in warm water before use. Instant yeast is dried into finer granules without that protective layer, so it can be mixed directly into dry ingredients without proofing first. Because water content differs so much between the fresh and dried forms, a straight 1:1 substitution by weight would badly under-yeast a recipe if you tried to sub fresh for dry.
This calculator uses Red Star Yeast's published conversion figures: multiply fresh yeast weight by 0.4 to get an equivalent weight of active dry yeast, or by 0.33 to get instant yeast. Some bakers use a simpler rule of thumb — divide fresh yeast weight by 2 (equivalent to ×0.5) — which is close enough for casual baking but runs slightly higher than Red Star's own figures; this tool defaults to the more precise 0.4/0.33 ratios. Active dry and instant yeast, on the other hand, are close enough in potency that they're commonly substituted 1:1 for each other by weight or volume, which is why a single packet (7g, 0.25oz, 2¼ teaspoons) is sold and used the same way for both.
One thing this converter can't fix: fresh yeast is considerably more perishable than either dried form, typically lasting only 1–2 weeks refrigerated versus many months for a sealed packet of dry yeast. If a recipe specifically calls for fresh yeast's flavor or texture contribution (some artisan bread bakers prefer it), converting to a dry equivalent gets you a comparable rise but not necessarily an identical result.
Yeast amounts also interact with a few other kitchen substitutions worth knowing together: recipes substituting honey for sugar typically call for slightly less yeast in a bread dough — see the Honey to Sugar Converter for that adjustment.