How do you calculate green bean shrink?

Divide the green weight lost by the green starting weight and multiply by 100. With 165 lb lost from 1,000 lb of green, shrink is 16.5%, meaning you keep 835 lb of roasted coffee.

What is a normal green bean shrink percentage?

Light roasts typically lose 12-15%, medium roasts 15-17%, and dark roasts 18-20% or more. Most specialty roasters target somewhere in the 15-18% band depending on profile and green moisture.

Why does my roast loss keep changing?

Usually green moisture content, ambient humidity, batch size, or charge temperature. A profile that suddenly loses more weight often points to drier incoming green or a longer development time than intended.

How does shrink affect my cost per roasted pound?

Directly. If you pay $4 per green pound at 16.5% shrink, your roasted coffee costs about $4.79 per finished pound before labor and packaging, because every roasted pound carries the cost of the green that burned off.

Roast loss vs shrinkage: are they the same thing?

Yes, in roasting they are used interchangeably. Both refer to the weight reduction from green to roasted coffee. Just be sure everyone measures from the same green starting weight to compare batches fairly.

How do I hit a more consistent shrink target?

Measure green moisture on intake, hold batch size and charge temperature steady, and log drop time. Comparing actual shrink to target each batch surfaces drift before it reaches the customer's cup.

Coffee, Tea, Roasting & Dry Goods Processing calculator

Green Bean Shrink Calculator

Green bean shrink, also called roast loss or weight loss, is the percentage of green coffee weight that burns off as moisture and organic matter during roasting. Roasters track it batch by batch because it directly drives finished yield, cost per roasted pound, and roast consistency. A light roast might lose 12-14%, while a dark roast can shed 18-20% or more, so shrink is both a cost lever and a roast-development signal. Drifting shrink on the same profile is an early warning that green moisture, batch size, or roaster calibration has changed.

What this calculator does

Calculate green bean shrink from weight lost between green coffee receiving, roasting, and finished roasted inventory.
monitoring green coffee shrink and inventory variance
It computes shrink as green weight lost divided by green starting weight times 100, and reports the gap between your result and your target shrink.

Formula used

Green Bean Shrink = green coffee shrink weight ÷ green coffee starting weight × 100
Gap to target = target green bean shrink - green bean shrink

Inputs explained

Green coffee weight lost during roast:
Green coffee starting weight:
Target green bean shrink:

How to use the result

Use it after every roast or on a sampled basis to verify roast consistency, validate yield assumptions, and price finished coffee on actual loss.
It measures total weight loss only and cannot separate moisture loss from organic (dry matter) loss, which is what truly indicates development; pair it with a roast log for that.

Common questions

How do you calculate green bean shrink? Divide the green weight lost by the green starting weight and multiply by 100. With 165 lb lost from 1,000 lb of green, shrink is 16.5%, meaning you keep 835 lb of roasted coffee.
What is a normal green bean shrink percentage? Light roasts typically lose 12-15%, medium roasts 15-17%, and dark roasts 18-20% or more. Most specialty roasters target somewhere in the 15-18% band depending on profile and green moisture.
Why does my roast loss keep changing? Usually green moisture content, ambient humidity, batch size, or charge temperature. A profile that suddenly loses more weight often points to drier incoming green or a longer development time than intended.
How does shrink affect my cost per roasted pound? Directly. If you pay $4 per green pound at 16.5% shrink, your roasted coffee costs about $4.79 per finished pound before labor and packaging, because every roasted pound carries the cost of the green that burned off.
Roast loss vs shrinkage: are they the same thing? Yes, in roasting they are used interchangeably. Both refer to the weight reduction from green to roasted coffee. Just be sure everyone measures from the same green starting weight to compare batches fairly.

Last reviewed 2026-05-12.