Yeast Conversion Calculator Formula

Understand the math behind the yeast conversion calculator. Each variable explained with a worked example.

Use the Yeast Conversion Calculator

Formulas Used

Active Dry Yeast

active_dry = fresh_yeast * 0.4

Instant (Rapid-Rise) Yeast

instant = fresh_yeast * 0.33

Active Dry Yeast

active_dry_tsp = (fresh_yeast * 0.4) / 3

Instant Yeast

instant_tsp = (fresh_yeast * 0.33) / 3

Variables

VariableDescriptionDefault
fresh_yeastFresh (Cake) Yeast(g)21

How It Works

How to Convert Between Yeast Types

Conversion Ratios

Fresh Yeast : Active Dry : Instant = 3 : 1.2 : 1

Or equivalently:

  • Active Dry = Fresh x 0.4
  • Instant = Fresh x 0.33
  • Fresh = Instant x 3

    • Notes

    One packet of active dry yeast is 7 g (2.25 tsp). One packet of instant yeast is also 7 g.

    Worked Example

    A recipe calls for 21 g fresh yeast. Convert to active dry and instant.

    fresh_yeast = 21
    1. 01Active dry: 21 x 0.4 = 8.4 g (about 2.8 tsp).
    2. 02Instant: 21 x 0.33 = 6.93 g (about 2.3 tsp).
    3. 03Use slightly more than 1 packet of either dry yeast.

    Ready to run the numbers?

    Open Yeast Conversion Calculator