THE NUMBERS, EXPLAINED
How to use this calculator.
Supported rule: initial refund is returned-item share of original bundle price, then the merchant may recover discount on retained items up to a stated cap. Refund never goes below zero.
Start with your inputs
Enter original bundle amount paid, standalone prices of retained items, standalone prices of returned items, promotion reversal cap. Keep amounts in the units shown on each field. The example is a starting point, not a recommended value.
| Input | Example value |
|---|---|
| Original bundle amount paid | 100 |
| Standalone prices of retained items | 40,30 |
| Standalone prices of returned items | 50 |
| Promotion reversal cap | 30 |
A worked example
With the example inputs above, initial prorated refund is 41.666667. Change the inputs to explore your own scenario.
| Result | Example answer |
|---|---|
| Initial prorated refund | 41.666667 |
| Promotion discount recovered | 11.666667 |
| Adjusted refund | 30 |
| Retained-item net cost | 70 |
How this is calculated
Initial prorated refund
Allocate original payment by standalone price weights.
Promotion discount recovered
Compare retained standalone value with its original payment share and cap recovery.
Adjusted refund
Subtract promotion recovery from prorated refund, floored at zero.
Retained-item net cost
Subtract adjusted refund from original bundle payment.
Symbols and units
- a
- Original bundle amount paid
- b
- Standalone prices of retained items
- c
- Standalone prices of returned items
- d
- Promotion reversal cap
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
Supported rule: initial refund is returned-item share of original bundle price, then the merchant may recover discount on retained items up to a stated cap. Refund never goes below zero.
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?
Initial prorated refund; Promotion discount recovered; Adjusted refund; Retained-item net cost. 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: Supported rule: initial refund is returned-item share of original bundle price, then the merchant may recover discount on retained items up to a stated cap. Refund never goes below zero.
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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