Pinwheel Quilt Block — Cutting Chart for Any Size
2 fabrics · Difficulty 2 of 5
Pinwheel is a 2×2 block of 8 pieces. Cut sizes for 4″, 8″, 12″, 16″, 20″ are below; for any other size it divides into cleanly, type the size and the chart recomputes.
Set the finished sizeAt a glance
- Grid
- 2×2
- Pieces you cut
- 4 — subcutting turns them into the 8 in the sewn block
- Difficulty
- 2 of 5 — easy How this is scored
Set the size
Nearest sizes that cut cleanly:
- Squares for half-square triangles — Fabric A
- 6⅞″
- Squares for half-square triangles — Background
- 6⅞″
Reading focusCorner triangles frame the centre on pointhalf-square-triangle unit
- Construction lattice
- 2 modules wide × 2 modules high
- Unit mix
- half-square-triangle unit
- Piece count
- 4 to cut · 8 in the diagram
Cut these pieces
Column headings are the FINISHED block size — the size it will be once it is sewn. Every number in the table is the size to CUT, which includes ¼″ of seam allowance on each edge. Rows that are subcut on a diagonal are cut larger still, so the allowance survives the extra cuts.
Scroll sideways to see every size.
| Patch | 4″ | 8″ | 12″ | 16″ | 20″ |
|---|---|---|---|---|---|
| Squares for half-square triangles — Fabric ACut 2, cut once on the diagonal | 2⅞″ | 4⅞″ | 6⅞″ | 8⅞″ | 10⅞″ |
| Squares for half-square triangles — BackgroundCut 2, cut once on the diagonal | 2⅞″ | 4⅞″ | 6⅞″ | 8⅞″ | 10⅞″ |
Read the block
Match each fabric letter in the diagram to the same fabric name in the cutting table. The caption describes the generated geometry in text.
Fabrics in this block
- A — gold
- BG — background
Which sizes divide cleanly
Scroll sideways to see every column.
| Grid | Divides cleanly at | The first few sizes |
|---|---|---|
| 2×2this block | every 1″ | 1″, 2″, 3″, 4″, 5″, 6″ … |
| 3×3 | every 1½″ | 1½″, 3″, 4½″, 6″, 7½″, 9″ … |
| 4×4 | every 2″ | 2″, 4″, 6″, 8″, 10″, 12″ … |
| 5×5 | every 2½″ | 2½″, 5″, 7½″, 10″, 12½″, 15″ … |
| 7×7 | every 3½″ | 3½″, 7″, 10½″, 14″, 17½″, 21″ |
- A 5-patch block at 12″ would need 2.4″ units, which is not a mark on any ruler. Try 10″ or 12½″ instead — Sister's Choice is the 5-patch block on this site.
- A 7-patch block at 12″ would need 1.714…″ units, which is not a mark on any ruler. Try 10½″ or 14″ instead — Bear's Paw is the 7-patch block on this site.
More about the sizes that do not divide cleanly
The sizes in between
Every whole-inch Pinwheel size from 4″ to 20″ can be cut accurately on its 2×2 grid.
These sizes divide cleanly but sit between the main chart's columns — the same computed cuts, published here so they exist on paper too. Any other clean size still computes in the size input above.
Column headings are the FINISHED block size — the size it will be once it is sewn. Every number in the table is the size to CUT, which includes ¼″ of seam allowance on each edge. Rows that are subcut on a diagonal are cut larger still, so the allowance survives the extra cuts.
Scroll sideways to see every size.
| Patch | 9″ | 10″ | 11″ | 13″ | 14″ | 15″ |
|---|---|---|---|---|---|---|
| Squares for half-square triangles — Fabric ACut 2, cut once on the diagonal | 5⅜″ | 5⅞″ | 6⅜″ | 7⅜″ | 7⅞″ | 8⅜″ |
| Squares for half-square triangles — BackgroundCut 2, cut once on the diagonal | 5⅜″ | 5⅞″ | 6⅜″ | 7⅜″ | 7⅞″ | 8⅜″ |
About this block
- Pieces in the finished block
- 8
- Unit types
- half-square-triangle unit
- Divides cleanly at
- 1″, 2″, 3″, 4″, 5″, 6″, 7″, 8″, 9″, 10″, 11″, 12″, 13″, 14″, 15″, 16″, 17″, 18″, 19″, 20″ and 21″ finished.
- Also known as
- Windmill, Water Wheel, Fan Mill, Crow's Foot, Mosaic No. 9
- Attribution
- Ohio Farmer, 1898 (as Windmill)
- Fabric for one 12″ block
- ½ yd total, rounded up to the nearest ⅛ yard, assuming 40″ of usable width.
One triangle pairing repeats at every corner, and as drawn here the four diagonals frame the centre on point rather than spinning around it — read the diagram rather than assuming a twist. The two joining seams cross in the middle, where the allowances stack; press the last seam open to flatten that crossing.
Piecing order
Make the 4 half-square-triangle units.
Lay out row 1 of 2 and sew its pieces together, left to right.
Lay out row 2 of 2 and sew its pieces together, left to right.
Join the 2 rows, matching the seams.
Cutting oversize
The chart gives the standard cut sizes, nothing padded. Some quilters cut this block's triangle units a little oversize and trim back — published allowances genuinely disagree on how much, so the range with its sources is on how to square up a quilt block.
History
Few blocks have collected more names: the recorded list runs from Windmill and Water Wheel to Fly, Crow's Foot and Kathy's Ramble, and the Ladies Art Company filed it as Mosaic No. 9 in their numbered mosaic series. The Ohio Farmer printed it as Windmill in 1898. Two fabrics and four half-square triangles make the whole design; every name is something someone saw in the turning.
Sources: Generations Quilt Patterns — Pinwheel.
Common questions
What size can I make Pinwheel?
Any size it divides cleanly: 1″, 2″, 3″, 4″, 5″, 6″, 7″, 8″, 9″, 10″, 11″, 12″, 13″, 14″, 15″, 16″, 17″, 18″, 19″, 20″ and 21″ finished. The chart above carries 4″, 8″, 12″, 16″, 20″ ready-worked, and the size input computes any other clean size without you doing arithmetic — every value computed by Quilt Block Atlas, none transcribed.
How many pieces are in a Pinwheel block?
8 pieces make up the sewn block, but you cut 4. The difference is method: triangle units are cut as squares and subcut, so the chart's quantities are what your rotary cutter produces, not what you count in the diagram.
What sizes does a 2×2 block divide into cleanly?
1″, 2″, 3″, 4″, 5″, 6″, 7″, 8″, 9″, 10″, 11″, 12″, 13″, 14″, 15″, 16″, 17″, 18″, 19″, 20″ and 21″ finished. The step is half the grid this block's cutting sizes are computed on, and the clean-size table above marks this block's row with the other families beside it.
Is Pinwheel good for a beginner?
Yes — it scores 2 of 5, easy, on this site's computed scale: 8 pieces, with the half-square-triangle unit as its hardest unit. The scoring rule, and every block ranked by it, is on the difficulty page linked above.
How do finished size, sewn unfinished/trim size, and starting cut size differ?
Finished size is 12″ after the block is sewn into surrounding seams. Its sewn unfinished/trim size is 12½″ before those outer seams, derived with the plain-square allowance. Starting cut size is the method-specific input listed in the chart. Starting cut size equals the unfinished outer target only for a plain square or rectangle workflow; it is not generally the same for pieced triangle units.
Keep going
Related blocks
Where this block appears
- Every block in the library
- Quilt blocks for beginners
- 12 inch quilt blocks
- Quilt block sizes
- Half square triangle blocks
Calculators for this block
- Quilt block grid calculator
- Half square triangle calculator
- Quilt top size calculator
- Fabric yardage calculator
Reference
Before you print
Measure this square before you cut. It must be exactly 1 inch. If it isn't, your printer scaled the page — reprint at 100% or "Actual size", not "Fit to page".