Rehydration Calculator
Pop the bag of freeze-dried breast milk on the scale and enter the total weight. We'll subtract the bag and tell you exactly how much water to add to reconstitute to 87% water / 13% solids.
Tip: 1 mL of water ≈ 1 g, so millilitres and grams are interchangeable here.
Add this much water
Quick reference table
| Scale reading (g) | Powder (g) | Water to add (mL) | Total (mL) |
|---|
How the maths works
Breast milk is naturally about 87% water and 13% solids. Freeze-drying removes the water, leaving a powder of roughly 100% solids. To return the powder to fresh-milk consistency, we add enough water so the final mixture is 87% water by weight.
The bag itself weighs 6 g, so we subtract that from your scale reading before doing the maths.
powder (g) = scale reading (g) − 6
water (mL) = powder (g) × 0.87 / 0.13
≈ powder × 6.69
So a scale reading of 19 g (13 g of powder + 6 g bag) needs 87 mL of water, for a total of 100 mL of reconstituted breast milk.