Yeast Conversion Calculator
Convert yeast between fresh, active dry, and instant for any recipe.
Uses the baking standard: 1 tsp instant = 1.2 tsp active dry = 9.4 g fresh yeast.
Yeast conversion is necessary when a recipe calls for one type of yeast but you only have another. The three common yeast types differ in moisture content, activity level, and how they are used — but all three contain the same species of yeast (Saccharomyces cerevisiae) and produce equivalent leavening results when properly converted.
Standard conversion ratios:
Everything here is anchored to fresh yeast, and the other two are derived from it:
Fresh yeast → Active dry yeast: × 0.40 (use 40% the weight)
Fresh yeast → Instant yeast: × 0.33 (use 33% the weight)
Active dry yeast → Instant yeast: × 0.83 (about 17% less)
Instant yeast → Active dry yeast: × 1.21 (about 21% more)
You will see “use 25% less instant than active dry” quoted all over the place. That figure comes from a different starting pair, where active dry is taken as half the weight of fresh rather than 40% of it. Mixing the two sets is how people end up with three conversions that disagree: convert fresh to active, then active to instant, and you land somewhere other than converting fresh to instant directly. Pick one anchor and derive the rest, which is what this calculator does.
Conversion table by common amounts:
| Fresh Yeast | Active Dry Yeast | Instant Yeast |
|---|---|---|
| 7g (0.25 oz) | 2.8g (~0.9 tsp) | 2.3g (~¾ tsp) |
| 14g (0.5 oz) | 5.6g (~1¾ tsp) | 4.6g (~1½ tsp) |
| 21g (0.75 oz) | 8.4g (~2¾ tsp) | 6.9g (~2¼ tsp, 1 packet) |
| 42g (1.5 oz) | 16.8g (~5½ tsp) | 13.9g (~4½ tsp, 2 packets) |
Standard yeast packet sizes (US):
- Active dry yeast: 7g per packet (2¼ tsp)
- Instant yeast: 7g per packet (2¼ tsp)
A 7 g packet of active dry is not interchangeable with a 7 g packet of instant, even though the packets weigh the same. Instant is more concentrated, so a packet of instant leavens roughly 20% more flour than a packet of active dry.
Characteristics of each yeast type:
| Type | Moisture | Shelf Life | How to Use |
|---|---|---|---|
| Fresh (cake) yeast | ~70% | 2 weeks refrigerated | Crumble into warm liquid (70–80°F / 21–27°C) and dissolve before adding to dough |
| Active dry yeast | ~8% | 1–2 years sealed | Must be proofed: dissolve in warm liquid (105–115°F / 41–46°C) with a pinch of sugar for 5–10 minutes until foamy |
| Instant (rapid-rise) | ~5% | 1–2 years sealed | Mix directly into dry ingredients, no proofing needed; tolerates wider temperature range |
Water temperature for yeast activation:
| Temperature | Effect |
|---|---|
| Below 60°F (15°C) | Yeast barely activates, very slow rise |
| 70–80°F (21–27°C) | Optimal for fresh yeast |
| 105–115°F (41–46°C) | Optimal for active dry proofing |
| Above 140°F (60°C) | Kills yeast, bread will not rise |
Why convert rather than just use more of the same type? Fresh yeast is highly perishable and not available everywhere. Instant yeast is the most convenient — mix-in, no proofing, reliable activity. Active dry has a longer shelf life than fresh but requires proofing, which adds 5–10 minutes to prep time.
Worked example: converting a traditional recipe: Recipe calls for 30g fresh yeast (for a large 2-loaf batch). You only have instant yeast. Instant needed = 30g × 0.33 = 9.9g ≈ 10g instant yeast (just under 1½ standard packets).
Round up rather than down when you are stuck between packet sizes. Slightly too much yeast gives you a faster rise and a marginally yeastier flavour; slightly too little gives you a loaf that never quite gets there, and no amount of extra time fully rescues it.
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
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