Yeast Conversion Calculator
Convert fresh, instant and active dry yeast quantities for bread and baking.
Approximate conversion — yeast formulations vary, so use your packet's instructions when it gives a specific equivalent.
Different recipes can ask for fresh yeast, active dry yeast or instant yeast, and UK bread recipes often use the term fast-action yeast. They all perform the same basic job—fermenting the dough—but the forms are not always used in identical quantities.
This converter gives you a practical equivalent between the three common types and can also convert dry yeast between grams and teaspoons.
Yeast strength and formulation vary between manufacturers, so treat the result as a sensible baking estimate rather than an exact guarantee. If your yeast packet gives its own substitution or mixing instructions, follow the packet.
How to Use the Yeast Converter
Choose the type of yeast in your recipe, enter the quantity, then select the yeast you want to use instead.
Fresh yeast is measured in grams.
For active dry and instant/fast-action yeast, you can use grams or teaspoons. Weight is preferable when you have a kitchen scale because very small spoon measurements can be difficult to reproduce precisely.
The result updates immediately and shows the converted weight together with an approximate teaspoon equivalent when the target is dry yeast.
Fresh, Active Dry and Instant Yeast
Fresh yeast is moist compressed yeast, usually sold as a soft block. Because it contains much more water than dried yeast, a recipe normally needs a larger weight of fresh yeast than dry yeast.
Active dry yeastis a dried granular yeast. Traditional instructions often tell you to dissolve or proof it first, although some modern products can be mixed directly into the dough. Check the manufacturer's directions rather than assuming every active dry yeast is handled the same way.
Instant or fast-action yeasthas smaller granules and is normally designed to mix directly with the flour. In UK supermarkets, 'fast-action yeast' is a common label for this direct-mix style of yeast.
Conversion Assumptions Used
For this calculator we use the following practical defaults:
- Fresh yeast to dry yeast: multiply by 0.33
- Dry yeast to fresh yeast: divide by 0.33
- Active dry and instant/fast-action yeast: 1:1 by weight
So 20 g fresh yeast gives:
20 × 0.33 = 6.6 g dry yeast
The same 6.6 g is used whether the target is active dry or instant/fast-action yeast.
These values are useful general conversions, but they are not universal manufacturing standards. Some yeast brands publish different fresh-to-dry equivalents, which is why the packaging should take priority when it provides its own conversion.
Yeast Conversion Reference
| Recipe calls for | Practical equivalent |
|---|---|
| 10 g fresh | about 3.3 g dry |
| 15 g fresh | about 5 g dry |
| 20 g fresh | about 6.6 g dry |
| 21 g fresh | about 7 g dry |
| 30 g fresh | about 9.9 g dry |
| 7 g active dry | about 7 g instant |
| 7 g instant | about 7 g active dry |
| 7 g dry | about 21 g fresh |
Grams and Teaspoons
Dry yeast is easier to scale accurately by weight, particularly when the amount is small.
For the teaspoon option, this calculator uses the practical relationship:
7 g dry yeast ≈ 2¼ tsp
That works out at roughly:
1 tsp ≈ 3.11 g
The calculator rounds spoon results to useful eighth-teaspoon increments rather than showing awkward values such as 2.1736 teaspoons.
If the required quantity is less than ⅛ teaspoon, use a digital scale rather than trying to estimate it by eye.
Fresh yeast is not converted to teaspoons because its compressed texture makes volume measurement less useful.
Why Yeast Conversions Are Approximate
Yeast is a living ingredient, not simply another unit of measurement.
Two products both labelled 'instant yeast' can be formulated for slightly different uses. Fast-action products may also include processing aids or ingredients intended to change how quickly a dough begins fermenting.
The dough itself matters too. Temperature, hydration, salt, sugar and fat can all influence fermentation.
That means the converted quantity can be correct as a practical substitution while the new dough still takes a different amount of time to rise.
Watch the dough rather than treating the recipe's proving time as a strict deadline.
Do I Need to Proof Active Dry Yeast?
Not always.
Some modern active dry yeasts can be mixed directly into the flour, while other manufacturers still recommend dissolving or activating their product in warm liquid first.
Use the method printed on your yeast packet.
Instant and UK fast-action yeast are normally designed for direct mixing with the dry ingredients.
Worked Example
A bread recipe calls for:
20 g fresh yeast
You only have instant yeast.
The calculator uses:
20 × 0.33 = 6.6 g
Result:
About 6.6 g instant / fast-action yeast
For an approximate spoon equivalent:
6.6 ÷ 3.11 ≈ 2.12 tsp
Rounded to a practical kitchen measure:
about 2⅛ tsp
If your packet provides a different fresh-yeast equivalent, use the packet value.
FAQs
How much dry yeast replaces fresh yeast?
This calculator uses about one-third the fresh-yeast weight as its general dry-yeast estimate. For example, 21 g fresh yeast converts to roughly 7 g dry yeast. Manufacturer guidance can differ, so use a packet-specific conversion when one is provided.
Is instant yeast the same as fast-action yeast in the UK?
For this calculator they are grouped together because common UK fast-action products are direct-mix dried yeasts used in much the same way as instant yeast. Individual brands can still differ in formulation and recommended quantity, so always check the packet.
Can active dry yeast replace instant yeast?
Usually, yes. This calculator uses a 1:1 weight substitution between modern active dry and instant yeast. Active dry yeast can begin fermentation more slowly, so the dough may need longer to reach the same stage.
Should I measure yeast in grams or teaspoons?
Grams are preferable when accuracy matters, particularly for small batches or long fermentation. Teaspoons are convenient, but different granule sizes and measuring technique introduce more variation.
Why is my dough rising at a different speed after converting yeast?
A yeast conversion does not make fermentation time identical. Yeast formulation, dough temperature, room temperature, salt, sugar, hydration and enrichment can all affect the speed of the rise. Judge the dough by its expansion and texture as well as the clock.