Yeast Conversion Calculator

About the Yeast Conversion

Active dry, instant, and fresh yeast aren't interchangeable one-for-one by weight, because they differ in moisture content and how much live yeast is packed into a given mass, so swapping one for another without adjusting the amount can leave a dough under- or over-leavened.

How It Works

Enter an amount and the yeast type you have on hand, and the calculator converts it to an instant yeast equivalent first, then derives the matching active dry and fresh yeast amounts from that common baseline.

instant equivalent = amount × factor (active dry ×0.75, instant ×1, fresh ×1/3); active dry = instant ÷ 0.75; fresh = instant × 3

Formula & Methodology

Instant yeast is used as the calculation's anchor because it's the most concentrated and consistent of the three. Active dry yeast is roughly 25% less potent by weight, so converting it to instant equivalent multiplies by 0.75; going the other direction divides by 0.75. Fresh yeast is much more diluted with moisture, needing roughly three times the weight of instant yeast to deliver the same leavening power, so it multiplies by one-third going in and by three coming back out.

Step-by-Step: Calculating It By Hand

1Start with the weight of whichever yeast type the recipe or your pantry has on hand.
2Multiply by that type's conversion factor to find the instant yeast equivalent.
3Divide the instant equivalent by 0.75 to find the active dry yeast amount.
4Multiply the instant equivalent by 3 to find the fresh yeast amount.

Examples

A recipe calling for active dry yeast

7g of active dry yeast converts to about 5.25g of instant yeast, or about 15.75g of fresh yeast for the same leavening power.

Using up fresh yeast from the fridge

15g of fresh yeast converts to about 5g of instant yeast, or about 6.67g of active dry, for a recipe that only lists dry yeast amounts.

Advantages

Converts between all three yeast types at once from a single input, not just one pair
Uses instant yeast as a consistent anchor for accurate two-step conversions
Works for scaling any recipe's yeast amount regardless of which type is on hand

Common Mistakes

Substituting active dry yeast for instant yeast at a 1:1 ratio without adjusting for the potency difference
Treating fresh yeast's weight as equivalent to dry yeast's weight instead of accounting for its much higher moisture content
Not accounting for active dry yeast typically needing to be proofed in warm water first, unlike instant yeast which can be mixed directly into dry ingredients

Common Use Cases

Substituting whichever yeast type is on hand for what a recipe specifies
Converting a recipe written for fresh yeast to the more commonly available dry forms
Doubling or scaling a bread recipe's yeast amount accurately across yeast types

Frequently asked questions

What are the conversion ratios?

Instant yeast is about 25% more potent than active dry by weight, so use roughly 75% as much instant yeast to replace active dry. Fresh (cake) yeast is roughly 3 times the weight of instant yeast for an equivalent amount of leavening power.

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Conclusion

The three yeast types aren't different concentrations of the same thing measured differently, they genuinely contain different amounts of active yeast per gram, which is why a straight substitution by weight throws off a dough's rise. Anchoring the math to instant yeast keeps the active dry and fresh conversions consistent no matter which type a recipe or a pantry happens to start with.