Sourdough Starter Calculator

Calculate feeding amounts and plan your starter schedule for baking day.

Calculate Feeding Amounts

Include extra for waste (usually 20-50g more than recipe calls for)

Feed your starter with:

40g
Starter
80g
Flour
80g
Water

Total: 200g of mature starter

Understanding Feeding Ratios

Feeding ratios are expressed as starter : flour : water. For example, a 1:5:5 ratio means for every 1 part of starter, add 5 parts flour and 5 parts water by weight.

  • 1:1:1 - Fast fermentation (4-6 hours at room temp). Good for frequent baking.
  • 1:2:2 - Moderate pace (6-8 hours). Common for daily feeding.
  • 1:5:5 - Slower fermentation (8-12 hours). Less waste, good for less frequent baking.
  • 1:10:10 - Very slow (12-24 hours). Ideal for overnight levain builds.

Tips for a Healthy Starter

  • Feed your starter when it has peaked and starts to fall - usually when it has doubled in size.
  • Use a consistent flour for predictable results. Whole grain flours ferment faster than white flour.
  • Temperature affects fermentation speed. Warmer = faster, cooler = slower.
  • Use filtered or bottled water if your tap water is heavily chlorinated.
  • Store unused starter in the fridge and feed once a week if not baking regularly.