THE NUMBERS, EXPLAINED
How to use this calculator.
Steady-rate use with opening reserve held separately; no hygiene cycle recommendation or peak-demand guarantee.
Start with your inputs
Enter services per operating hour, towels per service, laundry round-trip time (hours), towels required ready at opening, towels currently serviceable. Keep amounts in the units shown on each field. The example is a starting point, not a recommended value.
| Input | Example value |
|---|---|
| Services per operating hour | 8 |
| Towels per service | 3 |
| Laundry round-trip time (hours) | 4 |
| Towels required ready at opening | 30 |
| Towels currently serviceable | 100 |
A worked example
With the example inputs above, towels entering wash per hour is 24. Change the inputs to explore your own scenario.
| Result | Example answer |
|---|---|
| Towels entering wash per hour | 24 |
| Circulating towels during laundry | 96 |
| Total par stock | 126 |
| Additional towels required | 26 |
How this is calculated
Towels entering wash per hour
Multiply service rate by towels consumed per service.
Circulating towels during laundry
Multiply towel demand by wash turnaround and round up.
Total par stock
Add opening reserve to laundry circulation.
Additional towels required
Compare modeled par stock with serviceable inventory.
Symbols and units
- a
- Services per operating hour
- b
- Towels per service
- c
- Laundry round-trip time (hours)
- d
- Towels required ready at opening
- e
- Towels currently serviceable
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
Steady-rate use with opening reserve held separately; no hygiene cycle recommendation or peak-demand guarantee.
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?
Towels entering wash per hour; Circulating towels during laundry; Total par stock; Additional towels required. 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: Steady-rate use with opening reserve held separately; no hygiene cycle recommendation or peak-demand guarantee.
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
MIT Operations Management: Queueing and Little’s Law ↗
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 →