THE NUMBERS, EXPLAINED
How to use this calculator.
Positions refer to buttonhole centres measured from the placket top. At least two buttons are required. This gives equal spacing, not a garment-specific stress-point layout.
Start with your inputs
Enter placket length (cm), top offset (cm), bottom offset (cm), button count. Keep amounts in the units shown on each field. The example is a starting point, not a recommended value.
| Input | Example value |
|---|---|
| Placket length (cm) | 60 |
| Top offset (cm) | 5 |
| Bottom offset (cm) | 5 |
| Button count | 6 |
A worked example
With the example inputs above, positions from top (cm) is 5, 15, 25, 35, 45, 55. Change the inputs to explore your own scenario.
| Result | Example answer |
|---|---|
| Positions from top (cm) | 5, 15, 25, 35, 45, 55 |
| Spacing (cm) | 10 |
How this is calculated
Positions from top (cm)
Start at b. Position i = b + i × (a−b−c)/(d−1), with i from 0 to d−1.
Spacing (cm)
(a−b−c)/(d−1).
Symbols and units
- a
- Placket length (cm)
- b
- Top offset (cm)
- c
- Bottom offset (cm)
- d
- Button count
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
Positions refer to buttonhole centres measured from the placket top. At least two buttons are required. This gives equal spacing, not a garment-specific stress-point layout.
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?
Positions from top (cm); Spacing (cm). 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: Positions refer to buttonhole centres measured from the placket top. At least two buttons are required. This gives equal spacing, not a garment-specific stress-point layout.
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: algebra and proportional reasoning ↗
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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