Yeast Conversion Calculator

How it works

Active dry and instant yeast are both dried yeast sold in ¼ oz (7 g) packets of 2¼ teaspoons. Fresh yeast, sold as moist cakes, still contains most of its water, so it takes more of it by weight to raise the same dough.

Manufacturers state the fresh-to-dry equivalence slightly differently. Fleischmann's says one small 0.6 oz cake equals one packet of dry yeast. Red Star sells a 2 oz cake and says one third of it (about ⅔ oz) equals one packet, so a whole cake equals three packets. Red Star's chart footnote equates each third of its 2 oz cake to a 0.6 oz cake, or one ¼ oz package, so Red Star's 0.375 and Fleischmann's 0.417 express the same equivalence rounded differently: ⅔ oz against 0.6 oz of fresh yeast per packet. King Arthur Baking multiplies fresh yeast by 0.33 to get dry yeast. The rule you pick sets the fresh-to-dry factor: 0.417, 0.375 or 0.33 by weight.

Between active dry and instant yeast, King Arthur Baking substitutes one for the other 1:1 by weight or volume, as does Fleischmann's when instant replaces active dry. Fleischmann's adds 25% when active dry replaces instant; that option applies only in that direction.

The result is shown by weight, and also in teaspoons and packets for dry yeast or in small (0.6 oz) and large (2 oz) cakes for fresh yeast.

Formula

recipe grams = amount × grams per unit
  1 packet = ¼ oz = 7.09 g = 2¼ tsp;  1 tsp dry = 3.15 g
  small cake = 0.6 oz = 17.0 g;  large cake = 2 oz = 56.7 g
fresh → dry:  dry g = fresh g × k     dry → fresh:  fresh g = dry g ÷ k
  k = 0.25 ÷ 0.6 = 0.4167 (Fleischmann's), 0.25 ÷ (2/3) = 0.375 (Red Star), 0.33 (King Arthur)
instant → active dry: × 1 (King Arthur) or × 1.25 (Fleischmann's);  active dry → instant: × 1

Example

The default, one 0.6 oz cake of fresh yeast, is 17.0 g. Under Fleischmann's rule that is 17.0 × 0.4167 = 7.1 g of instant yeast: 0.25 oz, 2.25 teaspoons, exactly one packet.

A 2 oz cake of fresh yeast under Red Star's rule is 56.7 × 0.375 = 21.3 g of dry yeast, three packets or 6.75 teaspoons, matching Red Star's chart (3 packages, 21 g, 6¾ teaspoons per 2 oz cake). Under King Arthur's rule, 21 g of fresh yeast is 21 × 0.33 = 6.93 g of instant yeast.

Assumptions and limitations

• Conversions are the manufacturers' and King Arthur Baking's published rules: Fleischmann's Yeast 101 (fleischmannsyeast.com, retrieved October 2026), Red Star yeast conversion chart (redstaryeast.com, updated August 2026), King Arthur Baking "Active dry versus instant yeast" (2022) and "How to bake with fresh yeast" (2023). They are rules of thumb that differ from each other by up to about 25%.
• A packet is taken as exactly ¼ oz (7.09 g) and 2¼ teaspoons, as printed by Fleischmann's and Red Star; packet labels and King Arthur's chart round this to 7 g. Teaspoon figures assume active dry and instant yeast have the same weight per teaspoon.
• Fresh yeast cakes have been sold in several sizes. The 0.6 oz and 2 oz sizes are the ones the manufacturers' rules are stated for; for any other cake, the weight in grams or ounces is the reliable input.
• Rise times change with the type of yeast, the dough temperature and the amount of sugar, and Red Star adds an extra packet when a dough has more than ½ cup of sugar per 4 cups of flour. The calculator converts the amount only.

Frequently asked questions