How much does your roast really lose?
Measure the shrinkage of a finished batch, or work backwards from the roasted weight an order needs. No signup. Computes in your browser.
Both calculators use the same unit. Switching converts what you have already entered.
Weight loss
15.0%
3.3 lb left as water and chaff
Each roasted lb costs
17.6% more
than the green that went in — a ×1.176 multiplier on green cost
Typical is 12–18%. Well under 12% may mean underdevelopment; above 18% is dark-roast territory — or a scale worth checking.
Green to charge
58.8 lb
50 lb roasted ÷ (1 − 15%)
Lost in the roaster
8.8 lb
At the expected loss above
Dividing by (1 − loss) — not adding 15% — is the difference between hitting the order and coming up short. See what the loss does to your cost per bag.
Questions
What the number is telling you.
Weight loss looks like trivia until it meets an invoice — then it is the quiet fifth of your cost of goods.
- What is a normal weight loss when roasting coffee?
- Most roasts lose 12–18% of the green weight. Light filter roasts typically land around 12–14%, medium roasts 14–16%, and dark roasts 17–20% or beyond. The spread comes from how much water and organic matter leaves the bean: moisture is the bulk of it, with chaff and gases making up the rest.
- Why does my weight loss vary between batches of the same coffee?
- Green moisture content is the usual culprit — a coffee at 11.5% moisture simply has more water to lose than the same lot months later at 9.5%. Charge weight, roast degree, ambient humidity, and even how soon you weigh after cooling (beans keep off-gassing) all move the number by fractions of a percent. Tracking loss per batch is how you notice a lot drying out in storage.
- How much green coffee do I need to roast to get 50 lb of roasted coffee?
- Divide the roasted target by (1 − expected loss). At 15% loss: 50 ÷ 0.85 ≈ 58.8 lb of green. Adding 15% to 50 lb instead gives 57.5 lb — 1.3 lb short, which on a wholesale order is the difference between filling it and roasting again.
- Does roast weight loss affect my cost per pound?
- Directly. The green you paid for includes the weight that evaporates, so the surviving roasted coffee carries the full invoice. At 15% loss, roasted cost per pound is green cost ÷ 0.85 — about 17.6% higher. That multiplier flows straight into your bag cost and margins.