About Quilt Block Atlas
Quilt Block Atlas is a free reference library of traditional quilt blocks, each resizable to any finished size its grid divides cleanly. Every chart and calculator answer is computed from one registered geometry dataset and one shared set of functions, then faces the same validation rules on every route.
How an answer reaches the atlas
- Source dataRegistered geometry or an attributed reference
- Shared ruleOne computational source, never a template copy
- Published surfaceAnswer, generated figure and semantic table
- VerificationRe-derived test or an explicit refusal
| Published output | Computational or data source | Diagram or table | Validation or refusal rule |
|---|---|---|---|
| Cutting charts and calculator answers | The registered block grid and the shared quilt-math functions. | Generated cutting tables, diagrams and worked examples. | Tests re-derive each result; unsupported grids and inputs fail closed. |
| Seam guidance | The reader’s derived 10-strip test on their own fabric, thread and machine. | A generated row result compares the sewn row with its derived target. | The result diagnoses that sewn row; it never invents a universal scant-seam number. |
| Triangle oversize-and-trim advice | Attributed published ranges, with each source named. | The square-up guide keeps the alternatives beside the exact trim target. | The site shows the sourced choices and does not select one for every reader. |
| Unsupported history or formulas | A verified reference or a supported computational rule; otherwise, nothing. | No placeholder diagram, table or historical aside is manufactured. | Unsupported history and formulas are omitted, not averaged or guessed. |
- Blocks in the library
- 18
- Calculators
- 5
- Guides
- 8
What's computed
Grid, piece count, cutting chart, yardage, difficulty score — all of it comes from the same small set of functions run against each block's grid. Give a finished size and the site works out every cut, in eighths of an inch, the same way for every block on the site. Ask for a size the grid can't divide cleanly and it says so, with the nearest sizes that do — instead of rounding quietly and letting you find out at the cutting mat.
What's craft judgment, not arithmetic
No universal number can tell you how a fabric, thread and machine will sew. The quarter-inch seam allowance page therefore uses your derived 10-strip test to diagnose your sewn row. Triangle oversize-and-trim advice is different: the square-up guide presents attributed published ranges with each source named, without choosing one range for every reader.
What this site won't guess
Block history, old pattern-company names and who first published a design aren't arithmetic — they're historical claims. Where a page states one, it names a verified source. Unsupported history and formulas are omitted, not averaged or guessed: a plausible answer that cannot be checked would be worse than no claim at all.
Who makes it
Quilt Block Atlas is a small, independent reference site, not tied to any pattern company or fabric shop. Every number on it can be checked the same way you'd check it yourself — read the chart, do the arithmetic, see if it matches. If a number looks off, send a correction; the three details that make it reproducible are listed there.
See the privacy policy for what data this site collects, which is nothing beyond what your own browser keeps on your own device.