Yeast Conversion Calculator
Choose the type of yeast your recipe uses and the type you have, enter an amount, and the converter shows the equivalent. Cubes, packets, spoons, cups, grams and ounces are all supported.
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Created by the Reeliy Editorial Team. Last updated: Oct 19, 2026
Yeast and its use in cooking
Baker's yeast is a single-celled fungus, Saccharomyces cerevisiae. Given moisture, warmth and sugars from the flour, it ferments, giving off carbon dioxide and a little alcohol. The gas is trapped by the gluten network, which is what makes bread dough rise, and the by-products add flavour that a chemically leavened loaf lacks.
Yeast comes in three common forms. They contain the same organism and behave alike once active, but they differ in moisture, concentration and handling, so the weight you need changes from one to the next.
Fresh, active dry and instant yeast
- Fresh yeast (also called cake or compressed yeast) is a moist, crumbly block. It is perishable, kept in the fridge for roughly a couple of weeks, and is usually crumbled into liquid or flour. It is the least concentrated form, so you use the most of it.
- Active dry yeast is dehydrated into small granules with a protective coat. It stores for months, but is best dissolved in warm water (around 40 °C) for several minutes before use.
- Instant yeast, sold as rapid-rise or bread-machine yeast, has finer granules that need no pre-dissolving and can be mixed straight into the flour. It is the most concentrated of the three.
Very hot liquid kills yeast. Keep water for dissolving yeast below about 55 °C, and avoid putting salt directly on the yeast, since concentrated salt slows it down.
Are the types interchangeable?
In most bread, rolls and pizza dough, yes. Replace one with another by adjusting the amount for the difference in concentration and, for active dry, allowing a few extra minutes to dissolve. Rise times can shift slightly, and fresh yeast is often said to give a mellower flavour, but the finished loaf will be very close.
The ratios are rules of thumb and different sources round them differently. This converter uses these weights: 1 part fresh = ½ part active dry = ⅓ part instant. If a result sits between two sensible quantities, use the smaller one and let the dough rise a little longer; a slow rise is better than an over-yeasted one.
Yeast conversion matrix
Multiply the weight of the yeast you start with by the number in the matching cell to get the weight of the yeast you are converting to.
| From \ To | Fresh | Active dry | Instant |
|---|---|---|---|
| Fresh | 1 | 0.5 | 0.3333 |
| Active dry | 2 | 1 | 0.6667 |
| Instant | 3 | 1.5 | 1 |
Yeast conversion examples
These examples can all be reproduced in the form above.
Fresh yeast to active dry yeast
A bread recipe calls for one 42 g cube of fresh yeast. Half of 42 g is 21 g of active dry yeast, which equals three 7 g packets. For a smaller amount, 25 g of fresh yeast is 12.5 g of dry.
Fresh yeast to instant yeast
One cube (42 g) of fresh yeast becomes 42 ÷ 3 = 14 g of instant yeast, and 25 g of fresh yeast becomes 8.333 g. A kitchen scale accurate to 0.1 g is useful at this scale.
Active dry yeast to instant yeast
A single 7 g packet of active dry yeast corresponds to 7 ÷ 1.5 = 4.667 g of instant yeast. In the other direction, 10 g of instant yeast stands in for 15 g of active dry.
Teaspoons and packets
Volume depends on granule size, so different brands will measure differently. The converter assumes active dry yeast weighs about 521 kg/m3 and instant about 634 kg/m3. On those figures a 7 g packet of active dry yeast is 2.73 US teaspoons, and a 7 g packet of instant yeast is 2.24 teaspoons. The 2¼ teaspoons usually printed on a US packet is a fair match for the instant figure; weigh whenever you can.
Yeast conversion tables
| Fresh yeast (g) | Active dry (g) | Instant (g) |
|---|---|---|
| 7 | 3.5 | 2.333 |
| 14 | 7 | 4.667 |
| 21 | 10.5 | 7 |
| 25 | 12.5 | 8.333 |
| 42 (one cube) | 21 | 14 |
| 50 | 25 | 16.667 |
| 84 | 42 | 28 |
| 100 | 50 | 33.333 |
| Active dry (g) | Fresh yeast (g) | Instant (g) |
|---|---|---|
| 3.5 | 7 | 2.333 |
| 7 (one packet) | 14 | 4.667 |
| 10 | 20 | 6.667 |
| 14 | 28 | 9.333 |
| 21 | 42 | 14 |
| 25 | 50 | 16.667 |
| 50 | 100 | 33.333 |
| Instant (g) | Active dry (g) | Fresh yeast (g) |
|---|---|---|
| 3 | 4.5 | 9 |
| 5 | 7.5 | 15 |
| 7 (one packet) | 10.5 | 21 |
| 10 | 15 | 30 |
| 14 | 21 | 42 |
| 20 | 30 | 60 |
Standard yeast packaging
The converter treats a cube of fresh yeast as 42 g, the size of the block sold in many European shops, and a packet of dry yeast as 7 g, the common sachet or the quarter-ounce envelope sold in the United States. Other brands differ, so read the weight on the label if your pack is not one of these.
Fresh yeast is never sold in packets and dry yeast is never sold in cubes. If you select one of those impossible pairings, the result box says so instead of showing a number. For other cooking conversions, try the recipe converter, and when a recipe swaps fats, the oil to butter converter and butter to oil converter.
Frequently asked questions
How much active dry yeast equals one cube of fresh yeast?
With the 42 g cube used here, 21 g of active dry yeast, which is three 7 g packets. The rule is half the weight of fresh yeast.
How do I convert fresh yeast to instant yeast?
Divide the weight of fresh yeast by 3. For example, 30 g of fresh yeast is 10 g of instant yeast.
Can I replace active dry yeast with instant yeast?
Yes. Use about two thirds of the weight, so 9 g of active dry becomes 6 g of instant, and you can add it straight to the flour.
Why does the converter say fresh yeast isn't in packets?
Because packets are a dry-yeast pack size. Fresh yeast is sold in blocks or cubes, so that combination of type and unit does not exist.
Cite this converter and page
If you use this page in your work, you can cite it as:
Reeliy Editorial Team. (2026). Yeast Conversion Calculator. Reeliy. https://reeliy.com/converters/yeast-converter“Yeast Conversion Calculator.” Reeliy, 2026, https://reeliy.com/converters/yeast-converter.