get FermentCalc

Yeast Conversion Calculator

A recipe calls for fresh yeast but you only have instant? Enter any amount and its type to get the equivalent weight in the other two forms, plus the typical amount for your flour weight.

g

Fresh yeast holds the most water, so it takes about 3x its instant equivalent to do the same work; active dry sits between at about 1.25x. Dissolve active dry in warm water first; instant mixes straight into the flour.

g

Plain lean breads use about 1% instant yeast of flour weight; enriched or sweet doughs go up to 2%, and long cold ferments drop to 0.5% or less. The recommendation rows follow the 1% rule of thumb.

Results

Active dry yeast
12.5g
Fresh yeast
30g

Recommended for 500 g of flour (1% instant rule)

Instant yeast
5 g
Active dry yeast
6.25 g
Fresh yeast
15 g

How the conversion works

The three forms differ mostly in moisture and cell health. Instant yeast is dried finest and bakes strongest by weight, active dry is coarser and about 1.25x weaker, and fresh cake yeast is roughly 3x weaker because about a third of its weight is water. Conversions are by weight, so a kitchen scale matters more than the spoon measure a recipe gives.

fresh = instant x 3; active dry = instant x 1.25 (any direction converts through instant)

Brewing the other kind of yeast math? The yeast pitching rate calculator sizes beer starters in billions of cells, and the gram to tablespoon calculator converts any pantry ingredient between spoons and weight.

Frequently asked questions

Can I substitute instant for active dry one-for-one?

Not quite - active dry runs about 25% weaker by weight, so a recipe asking for 8 g of active dry needs about 6.4 g of instant. Modern active dry also no longer strictly needs the warm-water bloom it is famous for, but proofing it in the water first still confirms the pack is alive before it touches your dough.

How do I swap fresh yeast for dry in a bread recipe?

Divide the fresh weight by three for instant, or by 2.4 for active dry: 30 g of fresh cake yeast equals about 10 g of instant or 12.5 g of active dry. Fresh yeast crumbles straight into the dough and keeps in the fridge for only a couple of weeks - it is the form most European bakeries use.

Does the 1% rule work for every dough?

It is the center of the range, not a law: lean loaves carried by a levain often use 0-0.5% commercial yeast as insurance, plain sandwich breads sit near 1%, and enriched or sweet doughs go to 1.5-2% because sugar slows fermentation. Cinnamon rolls and brioche are the classic high-end examples.