Finished vs unfinished block size
Finished size is the dimension after surrounding seams are sewn. Sewn unfinished — or trim — size is the assembled block before those seams. Starting cut size is the method-specific fabric input; only a plain square or rectangle starts at its sewn-unfinished size.
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Fabrics in this block
- A — gold
- BG — background
Finished, sewn unfinished and starting cut sizes
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| Finished size | 2″ | 3″ | 4″ | 4½″ | 6″ | 12″ |
|---|---|---|---|---|---|---|
| Plain square starting cutalso this square unit's sewn-unfinished trim size | 2½″ | 3½″ | 4½″ | 5″ | 6½″ | 12½″ |
| Half-square triangle starting squaresfinished + ⅞″, squares cut corner to corner | 2⅞″ | 3⅞″ | 4⅞″ | 5⅜″ | 6⅞″ | 12⅞″ |
| Hourglass (quarter-square) starting squaresfinished + 1¼″, squares cut on both diagonals | 3¼″ | 4¼″ | 5¼″ | 5¾″ | 7¼″ | 13¼″ |
A plain square starts at finished size plus ½″, which is also that square unit's sewn-unfinished trim size. Triangle methods start from larger squares because the allowance must survive diagonal seams: a half-square triangle adds ⅞″ and an hourglass adds 1¼″. Check the square-up target before trimming, and use the quarter-inch seam test if the sewn result drifts.
The half inch, drawn
A plain square for a 6″ finished patch starts and trims at 6½″. The 6″ finished dimension survives inside the surrounding seams. A pieced triangle unit may start from a larger square, but it still trims to finished size plus ½″.
Every chart here labels both sizes
Column headings are finished sizes; row labels distinguish trim targets from method-specific starting cuts.
- Bear's Paw
- Broken Dishes
- Card Trick
- Churn Dash
- Flying Geese
- Friendship Star
- Heart
- Jacob's Ladder
- Log Cabin
- Maple Leaf
- Nine Patch
- Ohio Star
- Pinwheel
- Rail Fence
- Sawtooth Star
- Shoofly
- Sister's Choice
- Square in a Square
Related pages
- Quilt block grid calculator Find a clean finished size and its cutting dimensions.
- Flying geese calculator Compare no-waste and stitch-and-flip flying-geese cuts.
- Why is my quilt block the wrong size? Diagnose seams, printing, sizing, or an uncuttable target.
- Quilt block glossary Look up the measurement and unit words used here.
- Quilt blocks for beginners Start with the lowest computed scores.
Common questions
What does "finished size" mean?
The size a block or patch measures once it is sewn into the quilt, with every surrounding seam taken. It is the size the design maths runs on — grids, layouts and the charts on this site all speak in finished sizes first.
Why is the unfinished size ½″ bigger?
Because a seam takes ¼″ from each piece it crosses, and a patch is crossed on both sides: ¼″ on the left and ¼″ on the right is ½″ across the width, and the same top to bottom. What you cut must carry that allowance, so the sewn-unfinished trim size is ½″ up. That does not make every method's starting cut the same size.
Which size do patterns list?
Read the pattern's label rather than inferring it from “12 inch block.” Every chart on this site labels the distinction: column headings are finished sizes, and every number in a chart is a starting cut size.
Is unfinished size the same as cut size?
Only for a plain square or rectangle: its starting cut already is the sewn unfinished piece. For half-square triangles, quarter-square triangles, flying geese and other pieced units, the starting cuts are method-specific inputs. Sew them first; the assembled unit then trims to its sewn-unfinished size.