Yeast Conversion Calculator
Convert yeast between fresh, active dry, and instant for any recipe.
Uses standard ratios: 1 tsp instant = 1.25 tsp active dry = 0.6 oz 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:
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: × 0.75 (use 75% the weight)
Instant yeast → Active dry yeast: × 1.33 (use 33% more)
Conversion table by common amounts:
| Fresh Yeast | Active Dry Yeast | Instant Yeast |
|---|---|---|
| 7g (0.25 oz) | 2.8g (~¾ tsp) | 2.3g (~½ tsp) |
| 14g (0.5 oz) | 5.6g (~1¾ tsp) | 4.7g (~1½ tsp) |
| 21g (0.75 oz) | 8.4g (1 packet) | 7.0g (1 packet) |
| 42g (1.5 oz) | 16.8g (2 packets) | 14.0g (2 packets) |
Standard yeast packet sizes (US):
- Active dry yeast: 7g per packet (2¼ tsp)
- Instant yeast: 7g per packet (2¼ tsp)
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 (about 1.5 standard packets).