THE NUMBERS, EXPLAINED
How to use this calculator.
Additional purge excludes measured retention, avoiding double counting. All retained coffee is treated as discarded.
Start with your inputs
Enter measured grinder retention (g/changeover), blend changeovers, additional purge (g/changeover), coffee purchase price (currency/kg). Keep amounts in the units shown on each field. The example is a starting point, not a recommended value.
| Input | Example value |
|---|---|
| Measured grinder retention (g/changeover) | 4 |
| Blend changeovers | 10 |
| Additional purge (g/changeover) | 6 |
| Coffee purchase price (currency/kg) | 20 |
A worked example
With the example inputs above, retained coffee loss (g) is 40. Change the inputs to explore your own scenario.
| Result | Example answer |
|---|---|
| Retained coffee loss (g) | 40 |
| Total purge and retention loss (g) | 100 |
| Coffee loss cost (currency) | 2 |
How this is calculated
Retained coffee loss (g)
Multiply retained mass by changeovers.
Total purge and retention loss (g)
Add additional purge and retained mass per changeover.
Coffee loss cost (currency)
Convert grams to kilograms and multiply by purchase price.
Symbols and units
- a
- Measured grinder retention (g/changeover)
- b
- Blend changeovers
- c
- Additional purge (g/changeover)
- d
- Coffee purchase price (currency/kg)
Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.
Assumptions and limits
Additional purge excludes measured retention, avoiding double counting. All retained coffee is treated as discarded.
Calculations use the values you enter. Blank or invalid inputs show an error instead of silently substituting zero. Results are displayed to useful precision; calculations retain the underlying numeric precision.
Questions about this tool
What does the result tell me?
Retained coffee loss (g); Total purge and retention loss (g); Coffee loss cost (currency). The result applies to the method and inputs described above. Check the units and assumptions before using it in a decision.
Why might another calculator differ?
Differences in units, rounding, timing or model definitions can produce different answers. Compare the input definitions and the method, rather than only the final number. For this tool: Additional purge excludes measured retention, avoiding double counting. All retained coffee is treated as discarded.
Are my inputs stored or sent to AI?
Calculations on this page happen in your browser. The separate AI question finder sends its submitted conversation to OpenAI; these calculator fields are not sent. Favourites and recent tool names are stored locally. A shared link contains the inputs you choose to include.
Further reading
OpenStax: Describe and Identify Cost Drivers ↗
Background reading; this does not imply endorsement or independent review of SumFizz.
Review status
Software example and browser checks are recorded in our quality report. No external expert review is claimed. Created with coding assistance; calculations run as ordinary browser code.
Read the quality report →