THE NUMBERS, EXPLAINED
How to use this calculator.
Identical circular cookies are placed on a rectangular grid using measured final diameter, gaps only between cookies, no tray-edge margin. No staggered packing.
Start with your inputs
Enter tray width and depth (cm), test-baked cookie diameter (cm), gap between baked cookies (cm), total cookies. Keep amounts in the units shown on each field. The example is a starting point, not a recommended value.
| Input | Example value |
|---|---|
| Tray width and depth (cm) | 40,30 |
| Test-baked cookie diameter (cm) | 8 |
| Gap between baked cookies (cm) | 2 |
| Total cookies | 25 |
A worked example
With the example inputs above, cookies per tray is 12. Change the inputs to explore your own scenario.
| Result | Example answer |
|---|---|
| Cookies per tray | 12 |
| Trays needed | 3 |
| Empty spaces across purchased trays | 11 |
How this is calculated
Cookies per tray
Fit diameter-plus-gap intervals along each tray dimension.
Trays needed
Round required cookies divided by tray capacity up.
Empty spaces across purchased trays
Subtract cookie count from total grid spaces on needed trays.
Symbols and units
- a
- Tray width and depth (cm)
- b
- Test-baked cookie diameter (cm)
- c
- Gap between baked cookies (cm)
- d
- Total cookies
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
Identical circular cookies are placed on a rectangular grid using measured final diameter, gaps only between cookies, no tray-edge margin. No staggered packing.
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?
Cookies per tray; Trays needed; Empty spaces across purchased trays. 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: Identical circular cookies are placed on a rectangular grid using measured final diameter, gaps only between cookies, no tray-edge margin. No staggered packing.
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: Geometric formulas ↗
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 →