Question 1

What does the reverse calculator do?

Accepted Answer

It takes raw ingredient weights — flour, water, starter, salt — and returns the effective baker's percentage values. Useful when you're ad-libbing a recipe and want to know the resulting hydration before mixing.

Question 2

Why is effective hydration different from water-to-flour ratio?

Accepted Answer

Because the starter contains both flour and water. If you have 450g added flour and 325g added water, but your 100g starter at 100% hydration brings in 50g more flour and 50g more water, the effective totals are 500g flour and 375g water — 75% hydration, not 72%.

Question 3

Does starter hydration matter here?

Accepted Answer

Yes. A stiff starter (50% hydration) at 100g contributes 67g flour + 33g water. A liquid starter (100%) at the same weight contributes 50g + 50g. The math is automatic in this calculator.

Reverse Hydration Calculator

When to use this

The gear that makes the math work