Rehydration Ratio Calculator
Convert between a dried weight and its rehydrated yield — in either direction — using typical rehydration ratios by food type.
Rehydration estimate
Two directions, one ratio
Each food’s typical ratio describes how many times its dried weight it becomes once soaked or simmered back to a fresh-like texture. Multiply a dried weight by the ratio to project the rehydrated yield, or divide a target rehydrated weight by the ratio to find how much dried product you need to start with.
The “water absorbed” figure is simply the difference between the two weights — useful for estimating how much soaking liquid a recipe will actually pull in.
Frequently Asked Questions
Why do different foods have such different ratios?
How much weight a dried food regains depends mostly on how much water it lost when it was dried and how its structure holds water back. Dried mushrooms are riddled with air pockets and soak up a lot of water quickly, while dried herbs are mostly surface area and barely change weight when rehydrated for cooking.
Does soak time or water temperature matter?
Yes — these ratios are typical midpoints, not physical constants. Hot water and longer soaking generally push a food closer to (or past) full rehydration, while a quick rinse or cold soak leaves it short of the ratio shown here.
Can I use this to plan how much dried food to pack or store?
That's exactly the reverse mode: enter the rehydrated (cooked) amount a recipe calls for, and the calculator works backward to the dried weight you need to start with — handy for meal planning, backpacking food, or converting a fresh recipe to use pantry-dried ingredients.
Is the water absorbed the same as the water lost during drying?
Not exactly — drying removes water down to a low final moisture content, but rehydrating rarely restores 100% of the original fresh weight, since some structural water and soluble solids are permanently changed by the drying process. The ratios here reflect a practical cooking rehydration, not a return to the exact fresh weight.
General cooking estimate only. Actual regain varies with soak time, water temperature, and cut size.