Coffee Roast Yield & Cost-per-Bag Calculator
Drop in green weight, pick the roast level, and set your retail bag size. Get the roasted weight, the number of bags it yields, and — once you add green price, packaging cost, and labor — the cost of goods per bag.
Educational tool only — not financial or business advice. Roast loss varies by green moisture content (varies by origin and crop year), roaster style, batch size, and roast curve. The reference percentages in the dropdown are commonly published averages; measure your own loss per batch and use the override to replace the table average. Green coffee prices are commodity-volatile — always price against your most recent landed cost, not last year's.
Coffee roast yield calculator
Your roast
Enter green weight, roast level, and bag size. Add costs to see cost-of-goods per bag.
End of first crack, before second — typical 16% weight loss.
Override roast loss %
Enter your own measured weight-loss from a recent roast (charge weight − drop weight, divided by charge weight, × 100). Leave blank or click Use table default to use the published average for the selected roast level.
12 oz (340 g) is the US specialty standard; 250 g and 8 oz are also common.
Costs (optional)
Use your most recent supplier invoice. Specialty green prices are commodity-volatile and vary widely by origin, lot, and importer — last year's figure won't reflect this year's market.
Bag + degassing valve + label + tin tie. Use your most recent supplier invoice for the actual unit cost.
Including roasting, cooling, bagging, sealing, and labeling — divide an hourly wage by the number of batches you typically produce in that hour.
8.40 pounds of roasted coffee — 16.0 percent loss. 11 bags.
Roasted yield & cost per bag
Want cost-of-goods per bag? Open Costs (optional) on the left and enter your green price, bag cost, and labor allocation.
How roast loss works (and why it matters for pricing)
Green coffee beans lose weight during roasting. Two things go: water (5–10% of the green weight, evaporating as the bean heats past about 220 °F) and organic mass (chaff plus volatile aromatics released during first and second crack). The combined loss is called roast loss, and it's the single biggest gap between the green price you paid and the cost of the roasted coffee you actually sell.
A light roast loses about 12–14% of green weight. A medium / City+ roast (the US specialty standard) loses about 14–17%. A medium-dark / Full City sits at 17–19%. Dark / Vienna runs 19–21%, and a French / Italian roast at the edge of second crack can hit 22% or more. A roaster who priced their 12 oz bags off "green cost × 16/12" is leaving the entire roast loss on the table — usually 15–20% of margin.
The math is straightforward but every roaster has to measure it for their own roastery, roaster, batch size, and roast curve. The calculator above starts you with the published averages from Sweet Maria's roast library, Royal Coffee / Genuine Origin, and the Specialty Coffee Association — override with your own measured loss percentage once you have it, and the bag count and per-bag cost update against your actual yield.
Reference: typical roast loss by roast level
| Roast level | Typical loss | ~ Drop temp | Landmark |
|---|---|---|---|
| Cinnamon / very light | 12% | 385 °F | Just before first crack |
| Light / Light City | 14% | 395 °F | First crack rolling |
| Medium / City+ | 16% | 415 °F | End of first crack, before second |
| Medium-dark / Full City | 18% | 435 °F | Start of second crack |
| Dark / Vienna | 20% | 450 °F | Second crack rolling |
| French / Italian | 22% | 465 °F | End of second crack, oily surface |
Reference data compiled from Sweet Maria's Roast Loss reference, Royal Coffee / Genuine Origin weight-loss guidance, and the Specialty Coffee Association's roasting educational materials. Your actual loss varies by bean (moisture content varies origin to origin), roast curve, batch size, and roaster — the figures above are starting points. Weigh a charge and weigh the cooled, settled roasted batch to measure your real loss.
Frequently asked questions
What is roast loss in coffee roasting?
Roast loss is the percentage of green coffee weight that disappears during the roast — moisture (5–10% of green weight), chaff, and organic mass volatilized as aroma. A typical medium-roast specialty coffee loses 14–17% of green weight; a French roast can lose 22% or more. The remaining weight is the roasted coffee available to bag and sell.
How much green coffee do I need for a 12 oz bag?
At a typical 16% medium-roast loss, you need about 14.3 oz of green coffee to yield one 12 oz roasted bag (12 ÷ 0.84 = 14.3 oz). For a 14% light roast, the green requirement is 13.95 oz; for a 20% dark roast, it climbs to 15 oz. The calculator above runs the math both directions — green-in to roasted-out, and bag-out back to per-bag cost.
How do I calculate cost per bag of roasted coffee?
Add three numbers: (1) green cost allocated to the bag — the green weight needed for that bag, times the price per pound or kilogram of green; (2) bag and packaging cost — the bag, label, valve, and tin tie; (3) labor allocated to the bag — your hourly wage divided by the batches you roast per hour, then divided by bags per batch. The calculator surfaces all three rolled together.
How do I measure my own roast loss?
Weigh the green charge before it goes into the roaster (the "charge weight"). Weigh the roasted batch after it has cooled and degassed for at least 30 minutes (the "drop weight" measured at room temperature, not hot off the cooling tray). Roast loss = (charge − drop) ÷ charge × 100. Track this for every batch in your roast log — patterns emerge by origin, by season, and by your roaster's age.
Does darker roast always mean more weight loss?
Yes, mostly — longer time in the roaster equals more time for moisture and organic mass to volatilize. There is a subtle exception: a slow, low-temperature drying phase can drive off more moisture without much development, producing a "longer roast" with similar weight loss to a faster medium roast. But in practical small-roaster terms, more time + higher final temperature = more loss.
Why does my actual roast loss differ from the reference table?
Three reasons. (1) Green moisture content varies by origin and crop year — a Sumatra at 12% moisture loses more than an Ethiopia at 9% moisture even at the same roast. (2) Roaster style and batch size affect heat transfer and convective drying. (3) Where you drop the batch matters: a few seconds before or after second crack changes loss by 1–2 percentage points. The reference table is a starting point; the override field lets you plug in your measured average.
From one batch to a roastery
A calculator runs the math once. Ardent Seller runs it across every batch: green inventory (by origin, lot, and arrival date), a roasting recipe that decrements green and credits roasted on every production run, a packaging inventory that decrements bags and labels per sale, and per-bag cost reports that update automatically when the green price moves or your roast loss shifts.
Green inventory by origin & lot
Track green coffee like any other raw material — origin, lot, importer, landed cost, and on-hand quantity that decrements per roast.
Production runs & yield logs
Log a roast as a production run — charge weight in, drop weight out, true per-batch yield. Patterns emerge over weeks.
Related resources
Coffee Roaster's Batch & Cupping Log
A working Excel workbook for small-batch coffee roasters — roast profile log (charge temp, first-crack time, drop temp, development ratio), SCA-style cupping scores by lot, a 4-component blend calculator, and per-bag costing that picks up the actual measured weight loss from each roast.
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From the blog
Articles that dig deeper into the topics this tool covers.
Coffee Roasting at Home: Tracking Green Bean Inventory, Roast Loss, and True Cost Per Bag
Green coffee loses 15-20% of its weight during roasting — and that vanishing weight takes your profit margins with it if you are not tracking it. Learn how to manage green bean inventory by origin lot, calculate roast loss per batch, and price your bags based on what they actually cost to produce.
Batch Tracking for Food Sellers: Why Every Jar, Bag, and Box Needs a Paper Trail
Batch tracking protects your food business from recall disasters, builds customer trust, and keeps you ahead of tightening regulations. Learn how to set up a simple lot tracking system that works.
Recipe Costing 101: How to Calculate the True Cost of Every Product You Make
Learn how to calculate the real cost of every product you make — from raw ingredients to labor and overhead — so you can price with confidence and protect your profit margins.