THE NUMBERS, EXPLAINED
How to use this calculator.
Delivery arrives at the start of each cycle, then constant consumption occurs. Negative closing balances indicate unmet demand; no perishability model.
Start with your inputs
Enter starting inventory (units), delivery quantity (units), delivery interval (days), consumption (units/day), delivery cycles to project. Keep amounts in the units shown on each field. The example is a starting point, not a recommended value.
| Input | Example value |
|---|---|
| Starting inventory (units) | 5 |
| Delivery quantity (units) | 10 |
| Delivery interval (days) | 7 |
| Consumption (units/day) | 1 |
| Delivery cycles to project | 3 |
A worked example
With the example inputs above, closing inventory after each cycle is 8, 11, 14. Change the inputs to explore your own scenario.
| Result | Example answer |
|---|---|
| Closing inventory after each cycle | 8, 11, 14 |
| Net inventory change per cycle | 3 |
| Projected shortage at worst cycle (units) | 0 |
How this is calculated
Closing inventory after each cycle
For each completed cycle add deliveries and subtract interval consumption.
Net inventory change per cycle
Subtract cycle consumption from delivered quantity.
Projected shortage at worst cycle (units)
For this linear trajectory inspect first and final closing balances.
Symbols and units
- a
- Starting inventory (units)
- b
- Delivery quantity (units)
- c
- Delivery interval (days)
- d
- Consumption (units/day)
- e
- Delivery cycles to project
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
Delivery arrives at the start of each cycle, then constant consumption occurs. Negative closing balances indicate unmet demand; no perishability model.
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?
Closing inventory after each cycle; Net inventory change per cycle; Projected shortage at worst cycle (units). 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: Delivery arrives at the start of each cycle, then constant consumption occurs. Negative closing balances indicate unmet demand; no perishability model.
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: Solve proportions and their applications ↗
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.
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