THE NUMBERS, EXPLAINED
How to use this calculator.
Uses finished dimensions. Sashing lies only between blocks, with cornerstones at intersections. Counts do not include cutting allowances, outer sashing or fabric yardage.
Start with your inputs
Enter finished block width (cm), finished block height (cm), rows, columns, finished sashing width (cm), finished outer border width (cm). Keep amounts in the units shown on each field. The example is a starting point, not a recommended value.
| Input | Example value |
|---|---|
| Finished block width (cm) | 20 |
| Finished block height (cm) | 20 |
| Rows | 4 |
| Columns | 3 |
| Finished sashing width (cm) | 2 |
| Finished outer border width (cm) | 5 |
A worked example
With the example inputs above, finished quilt width (cm) is 74. Change the inputs to explore your own scenario.
| Result | Example answer |
|---|---|
| Finished quilt width (cm) | 74 |
| Finished quilt height (cm) | 96 |
| Blocks | 12 |
| Vertical sashing pieces | 8 |
| Horizontal sashing pieces | 9 |
| Cornerstones | 6 |
How this is calculated
Finished quilt width (cm)
Columns × block width + (columns−1) × sashing + 2 × border.
Finished quilt height (cm)
Rows × block height + (rows−1) × sashing + 2 × border.
Blocks
Rows × columns.
Vertical sashing pieces
Rows × (columns−1).
Horizontal sashing pieces
Columns × (rows−1).
Cornerstones
(Rows−1) × (columns−1).
Symbols and units
- a
- Finished block width (cm)
- b
- Finished block height (cm)
- c
- Rows
- d
- Columns
- e
- Finished sashing width (cm)
- f
- Finished outer border width (cm)
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
Uses finished dimensions. Sashing lies only between blocks, with cornerstones at intersections. Counts do not include cutting allowances, outer sashing or fabric yardage.
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?
Finished quilt width (cm); Finished quilt height (cm); Blocks; Vertical sashing pieces; Horizontal sashing pieces; Cornerstones. 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: Uses finished dimensions. Sashing lies only between blocks, with cornerstones at intersections. Counts do not include cutting allowances, outer sashing or fabric yardage.
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 and arithmetic ↗
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 →