THE NUMBERS, EXPLAINED
How to use this calculator.
One meal per supplied attendance day at constant price. Top-up day is an attendance-day index starting at 1, not a calendar date.
Start with your inputs
Enter current lunch balance, meal price, scheduled lunch attendance days, desired ending balance. Keep amounts in the units shown on each field. The example is a starting point, not a recommended value.
| Input | Example value |
|---|---|
| Current lunch balance | 25 |
| Meal price | 3 |
| Scheduled lunch attendance days | 10 |
| Desired ending balance | 5 |
A worked example
With the example inputs above, whole meals funded is 8. Change the inputs to explore your own scenario.
| Result | Example answer |
|---|---|
| Whole meals funded | 8 |
| First attendance day needing top-up | 9 |
| Top-up for planned meals and ending balance | 10 |
How this is calculated
Whole meals funded
Divide current balance by meal price and round down.
First attendance day needing top-up
Return the first unfunded attendance day, or zero if the plan is fully funded.
Top-up for planned meals and ending balance
Add planned meal cost and ending balance, then subtract current balance.
Symbols and units
- a
- Current lunch balance
- b
- Meal price
- c
- Scheduled lunch attendance days
- d
- Desired ending balance
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
One meal per supplied attendance day at constant price. Top-up day is an attendance-day index starting at 1, not a calendar date.
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?
Whole meals funded; First attendance day needing top-up; Top-up for planned meals and ending balance. 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: One meal per supplied attendance day at constant price. Top-up day is an attendance-day index starting at 1, not a calendar date.
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.
Read the quality report →