Yeast Converter
Convert between fresh (cake) yeast, active dry yeast, instant yeast and sourdough starter. Enter the amount in grams, ounces, teaspoons or packets and get the equivalent of every type at once, plus how much flour and water to adjust when you switch to a starter.
Shows the yeast as a baker's percentage.
Water as % of flour in your starter (100% = equal weights).
How to use the Yeast Converter
- Enter the amount of yeast your recipe calls for.
- Pick the unit: grams, ounces, teaspoons, packets or 42 g fresh cubes.
- Choose the yeast type in the recipe and the type you have.
- Read the converted amount and the equivalents for every other yeast.
- Add your flour weight to see the baker's percentage, or set your starter hydration when converting to sourdough.
Yeast conversion formula
All commercial yeasts are the same species; they differ in how much water they contain and how they were dried. That makes conversion a simple weight ratio. This converter uses the widely used baker's ratio:
Fresh 2.5 : Active dry 1.25 : Instant 1 (by weight)
To convert, divide by the factor of the yeast you have and multiply by the factor of the yeast you want. Example: 25 g fresh yeast ÷ 2.5 = 10 g instant, and 10 g × 1.25 = 12.5 g active dry. Brands vary a little, so treat results as close starting points; watch the dough rather than the clock.
For teaspoons the calculator uses about 3.1 g per teaspoon of dry yeast (a 7 g packet ≈ 2¼ tsp).
Yeast conversion chart
| Fresh yeast | Active dry yeast | Instant yeast | Instant (tsp) |
|---|---|---|---|
| 5 g | 2.5 g | 2 g | ⅔ tsp |
| 10 g | 5 g | 4 g | 1¼ tsp |
| 17 g (0.6 oz cake) | 8.5 g | 6.8 g | 2¼ tsp |
| 21 g (½ cube) | 10.5 g | 8.4 g | 2¾ tsp |
| 25 g | 12.5 g | 10 g | 3¼ tsp |
| 42 g (1 cube) | 21 g | 16.8 g | 5½ tsp |
| 50 g | 25 g | 20 g | 6½ tsp |
Switching between yeast and sourdough starter
A starter is a mix of flour, water and wild yeast, so swapping it in changes the dough's flour and water too. For a 100% hydration starter, half its weight is flour and half is water. If you add 227 g of starter, take about 113 g of flour and 113 g of water out of the recipe. Going the other way, add those amounts back when you replace a starter with commercial yeast. Wild yeast is slower: plan on rises that take two to three times as long, and keep the dough warm (about 24–27 °C / 75–80 °F).
Frequently asked questions
How do I convert fresh yeast to dry yeast?
Use about 40% to 50% of the fresh yeast weight in dry yeast. A common baker's rule is fresh 2.5 : active dry 1.25 : instant 1 by weight, so 25 g of fresh yeast equals about 12.5 g of active dry or 10 g of instant yeast.
Can I use instant yeast instead of active dry yeast?
Yes. Instant yeast is a bit stronger, so use about 25% less by weight (or simply the same amount, which only speeds up the rise). You can mix instant yeast straight into the flour without dissolving it first.
How many grams are in a packet of yeast?
A standard US packet (envelope) of active dry or instant yeast contains 1/4 ounce, which is 7 g or about 2 1/4 teaspoons. A US cake of fresh yeast weighs 0.6 oz (17 g), and European fresh yeast cubes weigh 42 g.
How much sourdough starter replaces a packet of yeast?
A common rule of thumb is about 1 cup (227 g) of ripe, 100% hydration starter in place of one 7 g packet of dry yeast. Reduce the recipe's flour and water by the amounts inside the starter (about 113 g each) and allow a much longer rise.
Is rapid-rise yeast the same as instant yeast?
Rapid-rise and bread machine yeast are types of instant yeast, often with added enzymes for a faster first rise. They convert the same way as instant yeast.
How much yeast should bread dough have?
Most yeasted breads use about 0.5% to 1.5% instant yeast relative to flour weight, rich sweet doughs often more, and long cold fermentations much less. Enter your flour weight above to see your recipe's baker's percentage.
Why can't I measure fresh yeast with a teaspoon?
Fresh yeast is a moist, crumbly block, so its volume varies a lot depending on how it is packed. Weighing it is far more accurate, which is why this converter only accepts grams, ounces, cakes or cubes for fresh yeast.