Feed for the loaf ahead.

Start with a simple 1:2:2 feed. See the amounts first, then scale the build for your recipe and a little left to keep.

Start with a simple formula

One part starter. Two parts flour. Two parts water.

A 1:2:2 feed makes 100 g of starter.

Existing starter: 20g
Fresh flour: 40g
Fresh water: 40g

Start with a 100%-hydration starter. Use 80 g in your recipe and keep 20 g for your next feed.

Use this formula

All ratios are by weight. Watch the starter’s rise to judge readiness.

How the numbers work

Five parts, one jar.

A 1:2:2 feed has five parts altogether. Divide your target weight by five, then weigh out each part.

Target = recipe amount + reserve80 g + 20 g = 100 g

One part = target ÷ (1 + 2 + 2)100 ÷ 5 = 20 g

So add 20 g starter, 40 g flour and 40 g water. Change the target or ratio below for a different build.

Use a different feeding ratio

For a ratio of 1 : F : W, where F and W are the flour and water parts:

Seed starter = target ÷ (1 + F + W)
Fresh flour = seed starter × F
Fresh water = seed starter × W

02 / Into the starter jar

100.0g total starter

Seed starter: 20.0 g
Fresh flour: 40.0 g
Fresh water: 40.0 g

Final hydration: 100.0%. Use 80.0 g for your dough and keep 20.0 g for your next feed.

Weights are rounded to 0.1 g. Small rounding differences may occur. Allow separately for anything left on the jar or utensils.

Behind the numbers

One part seed. The rest is your feed.

A 1:2:2 ratio means one part existing starter, two parts fresh flour and two parts fresh water, all by weight. The calculator divides the total amount you want by the sum of those parts. Your reserve is included in that target, rather than added afterwards.

Target = starter for recipe + reserve
Seed starter = target ÷ (1 + flour parts + water parts)
Fresh flour = seed starter × flour parts
Fresh water = seed starter × water parts

A 100 g build

For 80 g in your recipe and 20 g to keep, a 1:2:2 feed contains 20 g seed, 40 g fresh flour and 40 g fresh water. With seed at 100% hydration, the final starter is also at 100% hydration.

Your seed still matters.

Equal additions of flour and water do not automatically make the whole build 100% hydration. A stiff or liquid seed changes the answer. The calculator splits the seed into its flour and water components, adds the fresh feed, and reports total water divided by total flour.

Seed flour = seed weight ÷ (1 + seed hydration / 100)
Seed water = seed weight − seed flour
Final hydration = (seed water + fresh water) ÷ (seed flour + fresh flour) × 100

Amounts are not a fermentation clock.

Flour, temperature, starter condition and feeding history affect how the build develops. Use a feeding method appropriate to your starter and observe its behaviour. The tool does not certify that a starter is mature, safe or ready to bake. It also does not compensate for evaporation or starter left on tools.

If a scale cannot resolve the displayed amounts, use an appropriate larger build or accept and record a small rounding difference. Do not confuse the precision on screen with the precision of your kitchen scale.

Sources & method

Quantities are calculated from the weight ratio you enter. No fixed peak-time prediction is applied.