Half square triangle quilt blocks
Half square triangle quilt blocks use quilting's most useful unit in different layouts — turn the same two-triangle square and it becomes a pinwheel, a chevron, a sawtooth or a field of diamonds. Browse the classic layouts and every HST-bearing block in this atlas, then use the shared cutting rule: cut the two starting squares ⅞″ bigger than the finished unit.
Finished, unfinished, and starting-square anatomy
Scroll sideways to inspect every label.
Bear's Paw7×7 Broken Dishes2×2 Card Trick3×3 Churn Dash3×3 Friendship Star3×3 Heart4×4 Jacob's Ladder4×4 Maple Leaf3×3 Pinwheel2×2 Shoofly3×3 Sister's Choice5×5
Finished unit 3″. Sewn unfinished or trim target 3½″. 2 at a time: 2 starting squares at 3⅞″ yield 2 units. 4 at a time: 2 starting squares at 5½″ yield 4 units. 8 at a time: 2 starting squares at 7¾″ yield 8 units. Current HST block roster: Bear's Paw, Broken Dishes, Card Trick, Churn Dash, Friendship Star, Heart, Jacob's Ladder, Maple Leaf, Pinwheel, Shoofly, Sister's Choice.
- Finished unit
- 3″
- Sewn unfinished or trim target
- 3½″
- 2 at a time
- 2 starting squares at 3⅞″ yield 2 units
- 4 at a time
- 2 starting squares at 5½″ yield 4 units
- 8 at a time
- 2 starting squares at 7¾″ yield 8 units
Classic half square triangle layouts
Every arrangement below is set from the same HST unit — rotated, and in two of them spaced with plain squares. The two named repeats are atlas blocks; the rest are field layouts you set row by row. All of them cut with the one rule further down the page.
Pinwheel setting The Pinwheel block set with plain alternate squares — the muslin centres read as a second on-point grid.8 HST units in the repeat
Pinwheel cutting chartBroken Dishes repeat The 2×2 Broken Dishes block tiled four times — mirrored pairs instead of rotation.16 HST units in the repeat
Broken Dishes cutting chartChevron Every row the same mirrored pair, so the dark halves stack into columns of arrows.16 HST units in the repeat
Printable cut-size chartDiamond field The chevron row mirrored every other row — the units melt into a lattice of on-point diamonds.16 HST units in the repeat
Squares to cut at any sizeSquare on point HST units point their dark halves inward around a field of solid squares — one big diamond.8 HST units in the repeat
Squares to cut at any sizeSawtooth stripe Every unit in the same orientation — a sawtooth stripe or border run.16 HST units in the repeat
Printable cut-size chart
The blocks
Bear's Paw 7×745 piecesDifficulty 5 of 5 — advanced
Broken Dishes 2×28 piecesDifficulty 2 of 5 — easy
Card Trick 3×328 piecesDifficulty 4 of 5 — experienced
Churn Dash 3×317 piecesDifficulty 3 of 5 — confident beginner
Friendship Star 3×313 piecesDifficulty 2 of 5 — easy
Heart 4×422 piecesDifficulty 3 of 5 — confident beginner
Jacob's Ladder 4×424 piecesDifficulty 4 of 5 — experienced
Maple Leaf 3×312 piecesDifficulty 2 of 5 — easy
Pinwheel 2×28 piecesDifficulty 2 of 5 — easy
Shoofly 3×313 piecesDifficulty 2 of 5 — easy
Sister's Choice 5×533 piecesDifficulty 4 of 5 — experienced
The rule
Scroll sideways to see every column.
| Finished unit | 3″ | 4″ | 6″ |
|---|---|---|---|
| Squares to cutCut 2, sew and cut once on the diagonal | 3⅞″ | 4⅞″ | 6⅞″ |
Column headings are the FINISHED unit size. Every number in the table is the size to CUT: the finished size plus ⅞″, which covers the seam allowance on all four edges plus the diagonal.
Two, four or eight at a time
Two at a time gives you the most control: the seams go in before the cut, and the units need only a light trim. Four at a time is faster, but the cut runs across every seam, so all four edges come out on the bias — press gently and trim to size. Eight at a time turns two big squares into eight matching units, quickest when a block wants a stack of them; at large sizes the starting square outgrows the width of the fabric, and the calculator will tell you when. Fabric-wise there is nothing to choose between the three — they cost close to the same per unit.
Work out the squares to cut at any finished size
More from Quilt Block Atlas
- Quilt blocks for beginners Start with the lowest computed scores.
- 12 inch quilt blocks Compare blocks that divide cleanly at 12 inches.
- Quilt block sizes Compare clean steps, cuttable eighths, and refused sizes.
- Half square triangle calculator Compare two-, four-, and eight-at-a-time HST starting squares.
- Half square triangle chart Print every HST starting square from one chart.
- Quilt block glossary Look up the measurement and unit words used here.
Common questions
What is a half square triangle?
A square unit made of two right triangles joined on the diagonal — one fabric on each side of the seam. It reads as a triangle in the block, but you always cut and sew it as squares; the triangles are never cut loose.
What size squares do I cut for a half square triangle?
The finished unit size plus ⅞″, for the two-at-a-time method in the chart above. The extra covers the seam allowance on every edge plus the diagonal seam. Four- and eight-at-a-time start from different squares — the calculator gives all three at any size.
Should I make HSTs 2, 4 or 8 at a time?
Choose by yield and edge handling: two at a time makes two units, four at a time makes four with exposed bias edges, and eight at a time makes eight matching units. Compare their derived starting cuts in the method table above.
Why are my HSTs coming out too small?
Check the seam and starting cut. On the diagonal, extra seam depth comes out of both triangles at once, so the unit lands under size. Check that you cut the full size — the eighth-inch fractions matter here — and if you cut four or eight at a time, trim each unit to its unfinished size before it goes into the block.