Convert fresh, active dry and instant yeast
Recipes ask for the yeast the author had in the cupboard, and you rarely have the same. This yeast conversion calculator turns fresh yeast into active dry or instant yeast, and back, and shows the answer in grams, level teaspoons and whole packets or cubes. You type the amount, say what it is measured in and which yeast the recipe names, and the table lists all three.
A second panel handles the question bakers ask next: how to replace yeast with sourdough starter. It tells you how much starter to add and takes the flour and water that starter carries out of the recipe, so the dough keeps its balance. Everything runs in your browser.
How to use the Yeast Converter
- Enter the yeast amount from the recipe and choose grams, level teaspoons or packets (or cubes for fresh yeast).
- Choose the type of yeast the recipe uses and, if you like, the ratio set.
- Read the three rows: the one you started with is highlighted, the others are what to use instead.
- For sourdough, enter the recipe’s flour and water, the starter share and its hydration, and use the amounts listed.
Yeast Converter features
Three yeasts, three units
Grams, teaspoons (dry yeast) and packets or cubes for every row.
Two ratio sets
The common 3 : 1.25 : 1 ratio, or the older rule that dry yeast weighs half of fresh.
Editable sizes
Packets are 7 g by default and fresh cubes 42 g, but you can match your own pack.
Starter rebalancing
Flour and water inside the starter are subtracted from the recipe so hydration holds.
The ratios behind the numbers
Fresh yeast is mostly water, so it takes about three times as much by weight as instant yeast for the same rise. Active dry yeast has a tougher outer layer and a few dead cells, so it is used at about 25 per cent more than instant. That gives the common 3 : 1.25 : 1 set: 21 g fresh, 8.75 g active dry and 7 g instant do the same job in a standard loaf. An older rule says to use half as much dry yeast as fresh, which is the second option here; with instant yeast it works out near 0.4. The truth for your dough lies in that small window, and the packet instructions are the best tie-breaker.
A level teaspoon of dry yeast weighs about 3 g, so a 7 g packet is a little over 2 teaspoons. Fresh yeast is crumbled and weighed, which is why this tool does not give teaspoons for it.
Active dry versus instant in practice
- Instant yeast can be stirred straight into the flour.
- Active dry yeast is traditionally dissolved in warm water (about 40 °C) for 5–10 minutes first, and the water counts towards the recipe’s liquid.
- Fresh yeast is crumbled into the liquid or flour. It keeps for only a couple of weeks in the fridge and freezes well in small portions.
Replacing yeast with sourdough starter
A starter is wild yeast and bacteria in a paste of flour and water, so the calculation is about weights, not teaspoons. A starter of 20 per cent of the flour weight is a typical amount for a loaf that rises over several hours; use more for a quicker rise and less for an overnight proof. At 100 per cent hydration the starter is half flour and half water, so 100 g of starter removes 50 g of flour and 50 g of water from the recipe. Lower hydration shifts that split. Expect a more sour flavour, a longer rise and a different crumb, and judge the dough by volume, not by the recipe’s original time. Use the baker’s percentage calculator to rebuild a formula around the new flour weight, and the recipe scaler to resize it.
Yeast Converter FAQ
How do I convert fresh yeast to dry yeast?
Divide the fresh weight by about 2.4 for active dry yeast (multiply by 5/12), or by 3 for instant. For 30 g of fresh yeast that is 12.5 g active dry or 10 g instant.
Can I swap active dry yeast for instant yeast?
Yes. Use about 20 per cent less instant than active dry by weight, or the same amount if the dough is not in a hurry. Active dry is best dissolved in warm water first.
How many teaspoons are in a packet of yeast?
A 7 g packet holds about 2 1/4 level teaspoons of dry yeast, which is the usual amount for one 500 g loaf. Sizes vary by brand and country, so check your pack.
How much sourdough starter replaces yeast?
A common choice is a starter weighing about 20 per cent of the flour, with the flour and water it contains taken out of the recipe. The rise takes several hours longer than with commercial yeast.
Does this work for bread machines and pizza dough?
The ratios do. Bread machine recipes are written for instant or “bread machine” yeast, so convert from that, and expect pizza dough made with starter to need an overnight rise.
Why does my converted dough rise slowly?
Cold rooms, old yeast and salt touching the yeast all slow a rise. Check the yeast is in date, use warm liquid, and watch the dough rather than the clock.