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Calcimator

Yeast Pitch Rate Calculator

Calculate the optimal yeast cell count for fermentation based on batch volume, original gravity, beer style, and yeast viability.

Inputs

gallons
points
%

Results

Billion Cells Needed

187 billion

Yeast Packs Needed

1.9 packs

Recommended Starter Size1 liters
Degrees Plato12.5 °P
How to Use This Calculator
  1. Enter batch volume in gallons and original gravity (OG points).
  2. Select beer style (ale or lager — lagers require higher pitch rates).
  3. Set yeast viability (%) based on package date.
  4. Review Billion Cells Needed, Yeast Packs Needed, and Starter Size (L) if cells are insufficient.

How the result changes with Yeast Viability

Yeast ViabilityBillion Cells NeededYeast Packs Needed
19934 billion9.3 packs
42422 billion4.2 packs
69257 billion2.6 packs
91195 billion1.9 packs

What each input means

Batch Volume
Volume of wort to be fermented in gallons.
Original Gravity
Original gravity in points (e.g., 50 means OG 1.050). Higher gravity beers need more yeast.
Beer Style
1 = Ale (0.75 million cells/mL/°P), 2 = Lager (1.5 million cells/mL/°P). Lagers need roughly double the yeast.
Yeast Viability
Estimated viability of the yeast. Fresh liquid yeast is ~95-100%. Loses ~20% per month past production date.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Batch Volume = 5, Original Gravity = 50, Beer Style = 1, Yeast Viability = 95 = 4 input(s) provided
  2. Calculate Billion Cells Needed
    187 = 187
  3. Calculate Yeast Packs Needed
    Yeast Packs Needed
    1.9 = 1.9
  4. Calculate Recommended Starter Size
    Recommended Starter Size
    1 = 1
  5. Calculate Degrees Plato
    Degrees Plato
    12.5 = 12.5

Engine last updated . Checked against 2 independently-derived tests — how we verify calculators.

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