Convert between fresh yeast, active dry yeast, and instant yeast. Calculate equivalent amounts for any recipe with proofing guidance and storage tips.
Recipes from different countries and eras call for different yeast types, and substituting incorrectly is a common cause of bread failure. European recipes often specify fresh (cake) yeast, American recipes use active dry yeast, and bread machines call for instant (rapid rise) yeast. The Yeast Converter Calculator translates between all three types instantly.
The conversion ratios are straightforward but important to get right: fresh yeast is roughly 3× the weight of active dry yeast and 3.5× the weight of instant yeast. So if a recipe calls for 21g fresh yeast, you'd use 7g active dry or 6g instant. Getting these backwards — using 21g of instant yeast instead of 6g — would produce a massive, yeasty-tasting overrise.
This calculator goes beyond simple conversion. It accounts for packet sizes (¼ oz packets of active dry = 7g = 2¼ tsp), tells you whether proofing is needed, and adjusts for recipe size. It also covers osmotolerant yeast (SAF Gold) for sweet doughs and sourdough starter equivalents.
Using the wrong yeast amount is a top cause of bread failures. This converter ensures exact substitutions between fresh, active dry, and instant yeast for reliable results. This tool is designed for quick, accurate results without manual computation. Whether you are a student working through coursework, a professional verifying a result, or an educator preparing examples, accurate answers are always just a few keystrokes away.
Fresh Yeast = Active Dry × 3 = Instant × 3.5. Active Dry = Fresh ÷ 3 = Instant × 1.17. Instant = Fresh ÷ 3.5 = Active Dry × 0.86. 1 packet Active Dry = 7g = 2.25 tsp.
Result: 14g active dry yeast OR 12g instant yeast
42g fresh yeast ÷ 3 = 14g active dry (2 standard packets). 42g fresh ÷ 3.5 = 12g instant (about 4 tsp). This is typical for a large batch of bread using 2 kg flour.
Fresh yeast (also called cake or compressed yeast) is a moist block sold refrigerated. It has the mildest flavor and most reliable performance but spoils in 2–3 weeks. Active dry yeast is dehydrated and shelf-stable, with larger granules. Instant yeast (also called rapid-rise or bread machine yeast) is more finely ground, dissolves faster, and has slightly more living cells per gram.
Dehydrating yeast concentrates the cells, which is why you need less dry yeast than fresh. Active dry yeast has some dead outer cells (from the drying process) that instant yeast doesn't, which is why you need slightly more active dry than instant. The ratios (3:1 fresh-to-active-dry, 3.5:1 fresh-to-instant) account for these differences.
At altitudes above 3,500 feet, reduce yeast by 25% because lower air pressure lets dough rise faster. In cold kitchens (below 68°F), add 10–20% more yeast or allow more rising time. In warm kitchens (above 80°F), reduce yeast by 10–15% to prevent over-proofing.
Active dry yeast has larger granules and traditionally needs proofing (dissolving in warm water first). Instant yeast has finer granules and can be mixed directly into flour. They're otherwise interchangeable.
Modern active dry yeast (like Fleischmann's or Red Star) doesn't strictly need proofing, but it activates faster if you do. Proofing in warm (105–110°F) water for 5–10 minutes is good insurance.
Yes — instant yeast is ideal for bread machines. It's sometimes sold as "bread machine yeast." No proofing needed; just add it with the dry ingredients.
Unopened: cool, dry place for months. Opened: sealed container in the fridge (6 months) or freezer (12+ months). Bring to room temperature before using for fastest activation.
Osmotolerant yeast (like SAF Gold) is designed for high-sugar doughs (above 10% sugar). Regular yeast struggles in sweet doughs because sugar draws water away from yeast cells.
Roughly, 100g active starter (100% hydration) replaces 5g instant yeast, but fermentation time increases dramatically (4–12 hours vs 1–2 hours). Use this as a practical reminder before finalizing the result.