Yeast Converter
Swap between active dry, instant (rapid-rise), and fresh cake yeast. Enter the amount in teaspoons, grams, ounces, or packets/cakes and get the equivalent — using the 1 : 1.25 : 3 weight ratio bakers and yeast makers publish.
Example: with Amount 2.25 · Unit teaspoons · From Active dry yeast · To Instant / rapid-rise yeast → Use this instead: 1.8 tsp instant yeast (5.6 g).
- In grams5.6 g
- In packets / cakes0.80 standard ¼-oz (7 g) packets
Computed by the calculator below using its default values. Change any input to see your own numbers.
By weight: 1 g instant = 1.25 g active dry = 3 g fresh. A ¼-oz packet (7 g, 2¼ tsp) of active dry ≈ one 0.6-oz (17 g) cake of fresh yeast.
Why the 1 : 1.25 : 3 ratio exists
Fresh cake yeast is about 70% water, so you need roughly three times its weight to deliver the same living cells as instant yeast. Active dry sits in between: its coarser granules carry a coat of dormant and dead cells from the drying process, so bakers use about 25% more of it than instant. Those two facts produce the conversion this page uses — 1 g instant = 1.25 g active dry = 3 g fresh — the ratio published by yeast makers and baking references.
The packet math confirms it: a ¼-oz packet of active dry (7 g) converts to 16.8 g fresh, almost exactly the standard 0.6-oz (17 g) cake. That is why old recipes treat one packet and one cake as interchangeable.
What actually changes in the bowl
Swapping types changes speed more than quantity. Instant yeast is milled finer and wakes faster, so doughs rise 20–30% quicker; watch the dough, not the clock. And no conversion rescues expired yeast — if a dry yeast is old, proof a pinch in warm water with sugar and wait for foam before trusting a whole loaf to it.
How it’s calculated
Amounts convert through instant-equivalents by weight: active dry = 1.25 × instant; fresh = 3 × instant — the conversion convention published by yeast manufacturers and baking references. Units: 1 tsp dry yeast = 3.1 g (a 7-g packet is 2¼ tsp); fresh yeast ≈ 5 g per tsp (density ≈ 1 g/mL); 1 oz = 28.3495 g; packets are 7 g for dry yeast, cakes 17 g (0.6 oz) for fresh.
Ratios are conventions — for a single-packet home recipe, manufacturers say dry types can swap 1:1 and you simply watch the rise time instead.
Yeast equivalents by weight
| Instant | Active dry | Fresh (cake) |
|---|---|---|
| 1 tsp (3.1 g) | 1¼ tsp (3.9 g) | 9.3 g (about ½ cake) |
| 1.8 tsp (5.6 g) | 2¼ tsp (7 g = 1 packet) | 16.8 g (≈ 1 cake) |
| 2 tsp (6.2 g) | 2½ tsp (7.8 g) | 18.6 g |
| 1 tbsp (9.3 g) | 3¾ tsp (11.6 g) | 27.9 g (about 1⅔ cakes) |
Computed with the 1 : 1.25 : 3 weight ratio and 3.1 g per tsp of dry yeast; rounded to 0.1 g.
Common mistakes
- Converting the wrong direction — going from instant to active dry you add 25%, not subtract it.
- Equating a packet and a cake by weight: a packet is 7 g and a cake 17 g; they match in leavening power, not grams.
- Measuring fresh yeast with dry-yeast spoon math — crumbled fresh runs about 5 g per teaspoon versus 3.1 g for dry.
- Adding more yeast to fix a slow rise when the yeast is simply dead — proof it in warm water with a pinch of sugar first.
Frequently asked questions
How do I substitute instant yeast for active dry?
Multiply by 0.8: a recipe calling for 2¼ tsp active dry needs about 1.8 tsp instant. For a single-packet recipe, manufacturers say a straight 1:1 swap also works — the dough just rises a bit faster.
What ratio does this converter use?
By weight, 1 part instant = 1.25 parts active dry = 3 parts fresh cake yeast. All conversions pass through that ratio, with 3.1 g per teaspoon of dry yeast and 7-g packets / 17-g cakes.
How much fresh yeast equals one packet?
About 17 g — one standard 0.6-oz cake. The math: 7 g active dry ÷ 1.25 × 3 = 16.8 g fresh, which rounds to the cake.
What water temperature should I use?
Proof active dry at 105–115°F. Instant mixes straight into the flour and tolerates warmer liquid, about 120–130°F (Fleischmann's guidance). Above roughly 140°F you start killing yeast.
Is rapid-rise the same as instant yeast?
Functionally yes — same fine-granule yeast, sometimes with added enzymes or conditioners. Convert it 1:1 with instant, and expect the fastest rise of the three types.