Coffee Roast Yield Loss Calculator

Roast preset:

Start from a light, medium, dark, or production batch profile.

Weight unit:

Use the same unit that appears in your roast log.

Green coffee in:

Enter the batch charge weight before roasting.

Roasted coffee out:

Enter the post-roast output weight after cooling.

Target roast loss: {{ targetLossDisplay }}

Typical specialty roast loss often lands around 12-20%, with darker roasts higher.

QC/sample pull:

Subtracts from roasted output to show sellable roasted coffee.

Currency:

Used for cost and JSON output labels.

Green landed cost:

Cost per selected weight unit before roast loss.

{{ currency }}/{{ weight_unit }}

Batch overhead:

Added to green spend before cost-per-roasted-unit math.

{{ currency }}/batch

Roasted output target:

Useful for planning orders or bag counts before roasting.

Batch count:

Leave at 1 for a single measured roast.

Retail package size:

Enter a common bag size, such as 340 g, 12 oz, 1 lb, or 1 kg.

Green moisture estimate: {{ moistureDisplay }}

A simple estimate for interpreting loss, not a replacement for a moisture meter.

Metric	Value	Detail	Copy
{{ row.metric }}	{{ row.value }}	{{ row.detail }}

Cost item	Value	Use	Copy
{{ row.item }}	{{ row.value }}	{{ row.use }}

Plan item	Result	Action	Copy
{{ row.item }}	{{ row.result }}	{{ row.action }}

{{ jsonOutput }}

Enter positive green and roasted weights to calculate roast yield loss.

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Roasted coffee is always lighter than the green coffee that entered the roaster. Heat drives off water, carbon dioxide, volatile compounds, and chaff while the bean expands and changes color. That shrinkage is usually called roast loss, and it affects both flavor control and the amount of saleable coffee available after a batch cools.

Roast loss is often discussed as a roast-degree clue, but it is also a production number. A light filter profile may lose much less mass than a dark espresso profile. Green moisture, batch size, airflow, development time, endpoint temperature, scale workflow, and the timing of the post-roast weigh-in can all move the percentage. A roaster comparing batches needs the same green-in and roasted-out measurement points before treating the difference as a profile change.

Green coffee flowing through roast loss into roasted and sellable output

Commercial planning adds another step after the headline percentage. Cupping samples, color checks, grinder purges, and internal samples reduce what can be packed or sold. A batch that looks acceptable by roast loss can still miss a retail order if QC pulls, package size, or target-output planning are ignored.

The useful habit is to separate measurement from judgment. Roast loss can flag unusual development, scale mistakes, moisture changes, or target drift, but it cannot prove cup quality by itself. Sensory review, color, density, moisture history, and batch notes still decide whether the coffee matches the profile.

How to Use This Tool:

Use one cooled batch or a repeated profile, then add cost and packing assumptions only after the core weights are correct.

Choose a Roast preset or leave the fields as a custom batch. Presets load realistic green weight, roasted weight, target loss, QC pull, and cost values for common roast situations.
Set Weight unit, then enter Green coffee in and Roasted coffee out from the same batch. The roasted value must be positive and cannot exceed the green value.
Enter Target roast loss to compare measured loss against the profile expectation. A large drift points to a profile, moisture, or measurement review rather than an automatic defect.
Add QC/sample pull when coffee is removed before packing. This changes Sellable roasted coffee, Cost per sellable unit, and package planning.
Enter Green landed cost, Batch overhead, and Roasted output target when production cost or backward planning matters.
Open Advanced for Batch count, Retail package size, and Green moisture estimate. These affect package count, repeated-batch totals, and the moisture split shown in Production Plan.
Read Yield Ledger first, then review Cost Ledger, Production Plan, and Loss Sensitivity Chart when you need cost or target-output decisions.

Interpreting Results:

Roast loss percent is the main consistency signal. Roasted yield percent is the same relationship from the output direction, so the two add to 100% before QC pulls. Sellable roasted coffee is lower when cupping, color checks, purges, or samples are removed after roasting.

Roast-loss signal maps the measured percentage into a broad review range. It is a planning cue, not a quality grade.
Measured profile drift compares actual loss with the target. Values near zero mean the batch is close to the entered target loss.
Cost per roasted unit uses all roasted output before QC pull. Cost per sellable unit uses only sellable coffee after QC pull.
Full retail packages floors the package count, so any remainder should be handled as bulk, samples, staff coffee, or the start of another blend plan.

A normal-looking loss value can still hide a wrong weigh point. Recheck tare, cooled weight, batch identity, and QC removal before changing the roast profile or green draw.

Technical Details:

Roast loss is a mass balance. The starting green coffee is the denominator because the question is how much original material left the batch during roasting. The roasted weight is measured after cooling and before later removals. QC pulls do not change the roast loss percentage; they change sellable output and cost allocation.

The target comparison uses a planned loss percentage to estimate expected roasted output from the same green weight. When measured output is lower than expected, loss is above target. When measured output is higher than expected, loss is below target. The tool also separates the entered green-moisture estimate from additional loss so a roaster can see how much of the percentage is beyond likely water removal.

Formula Core:

The main equations convert green, roasted, QC, and package weights to one internal mass basis before returning values in the selected display unit.

\begin{array}{lcl} L_{pct} & = & \frac{W_{green} - W_{roasted}}{W_{green}} \times 100 \\ Y_{pct} & = & 100 - L_{pct} \\ W_{sellable} & = & (W_{roasted} \times N) - (W_{QC} \times N) \\ W_{green needed} & = & \frac{W_{target roasted}}{1 - \frac{L_{target}}{100}} \end{array}

Here N is batch count, WQC is the QC or sample pull per batch, and Ltarget is the target roast loss percent. Cost per sellable unit divides green spend plus batch overhead by Sellable roasted coffee; cost per package divides the same total by the number of full package fills.

Coffee roast loss ranges and review meaning
Measured loss	Signal	Review cue
Below 10%	Very low loss	Check tare, cooling state, very light development, or unusual moisture.
10% to below 13%	Light range	Often consistent with lighter roast development.
13% to 17%	Medium range	A common production range for many specialty profiles.
Above 17% through 22%	Darker range	Fits darker or longer development profiles.
Above 22%	High loss review	Check roast degree, moisture, scorching risk, or measurement error.

For a 12 kg green batch that cools to 10.2 kg, loss is 1.8 kg and roast loss is 15.0%. With a 0.2 kg QC pull, sellable output is 10.0 kg. If the batch cost is 112.80 in green coffee plus 18.00 overhead, cost per sellable kilogram is 13.08 before packaging, spoilage, margin, or other business costs.

Worked Examples:

Medium production batch

A 12 kg charge roasted to 10.2 kg returns Roast loss percent of 15.0% and Roasted yield percent of 85.0%. With a 15.0% target, Measured profile drift is on target, so the next check is sensory and color consistency rather than weight math.

Dark espresso with package planning

A 15 kg green batch roasted to 12.15 kg has 19.0% loss. If 0.25 kg is pulled for checks and the package size is 1 lb, Full retail packages floors the sellable output into whole bags and leaves a remainder for another use.

Target-output back calculation

To plan 10 kg roasted output at a 15.0% target loss, Green needed for target output is about 11.76 kg. If current measured loss is much higher, the same green draw will not satisfy the order.

Troubleshooting a blocked result

If Roasted coffee out is entered above Green coffee in, the result is invalid because roasted output cannot exceed the starting charge. Recheck the unit selector, tare, batch label, and cooled-weight entry before reading the ledgers.

FAQ:

Is roast loss the same as coffee quality?

No. Roast-loss signal is a weight-based review cue. Cupping, color, moisture history, density, and profile notes are still needed before judging quality.

Should QC samples be included in roast loss?

No. Enter QC samples in QC/sample pull. Roast loss uses green weight and cooled roasted weight before those samples are removed.

Why does cost per sellable unit exceed cost per roasted unit?

Cost per sellable unit spreads the same green spend and overhead across less coffee after QC pull, so it rises when sample or purge weight is removed.

What should I fix if the result says to add batch weights?

Enter positive Green coffee in and Roasted coffee out values in the selected weight unit, and make sure roasted output is not greater than green input.

Glossary:

Roast loss: The mass lost between green coffee in and cooled roasted coffee out, expressed as a percentage of green weight.
Roasted yield: The roasted output as a percentage of green input before QC pulls.
QC/sample pull: Roasted coffee removed for cupping, color checks, purge, training, or internal samples.
Sellable roasted coffee: Roasted output left after QC or sample removal.
Target loss: The expected roast loss percentage for a profile, coffee, or production plan.

References:

Roast Loss, Green Coffee Collective.
Understanding Roast Yield And Loss, Royal Coffee.
Definitions of Specialty Coffee, International Coffee Organization, October 1, 2025.