Quilt block · Four-patch · First quilt
Half-Square Triangle quilt block
One half-square triangle unit: a square cut once on the diagonal, a dark triangle and a light one. Also called Triangle Square and HST.
What to cut for one block
A 6″ finished block measures 6½″ before it’s sewn into a quilt. Each fabric’s yardage is the least that cuts its strips across the width of fabric, with a strip to spare for straightening.
Background · Snow in the picture
1 triangle
- A1 square 6⅞″cut once on the diagonal
Dark · Navy in the picture
1 triangle
- A1 square 6⅞″cut once on the diagonal
Worked out by @quarterinch/cutting · ¼″ seams included · strips cut across 42″ of usable width · the letters are the pieces the sewing steps name
A 9″ finished block measures 9½″ before it’s sewn into a quilt. Each fabric’s yardage is the least that cuts its strips across the width of fabric, with a strip to spare for straightening.
Background · Snow in the picture
1 triangle
- A1 square 9⅞″cut once on the diagonal
Dark · Navy in the picture
1 triangle
- A1 square 9⅞″cut once on the diagonal
Worked out by @quarterinch/cutting · ¼″ seams included · strips cut across 42″ of usable width · the letters are the pieces the sewing steps name
A 12″ finished block measures 12½″ before it’s sewn into a quilt. Each fabric’s yardage is the least that cuts its strips across the width of fabric, with a strip to spare for straightening.
Background · Snow in the picture
1 triangle
- A1 square 12⅞″cut once on the diagonal
Dark · Navy in the picture
1 triangle
- A1 square 12⅞″cut once on the diagonal
Worked out by @quarterinch/cutting · ¼″ seams included · strips cut across 42″ of usable width · the letters are the pieces the sewing steps name
How it’s sewn
For the 6″ block. Choose another size above and these steps follow it.
- Make 1 half-square triangle unit
Sew a Dark A triangle to a Background A triangle along their long edges. Press toward the Dark. Each measures 6½″ (6″ finished).
For the 9″ block. Choose another size above and these steps follow it.
- Make 1 half-square triangle unit
Sew a Dark A triangle to a Background A triangle along their long edges. Press toward the Dark. Each measures 9½″ (9″ finished).
For the 12″ block. Choose another size above and these steps follow it.
- Make 1 half-square triangle unit
Sew a Dark A triangle to a Background A triangle along their long edges. Press toward the Dark. Each measures 12½″ (12″ finished).
Blocks like it
The Little Cedar TreeFour-patch
London SquareFour-patch
Old Maid’s RamblerFour-patch
HourglassFour-patch
More like this: Four-patch quilt blocks · all quilt blocks
Questions
Short answers.
Something else? A real person replies.
hello@quarterinch.app
Is Half-Square Triangle the same block as Triangle Square?
Usually, yes. Block names vary by region and by book, and the same block is often sold under several. Our library lists Triangle Square and HST as other names for this one, so a search for any of them finds it.
What size should I make it?
Its 2 × 2 grid lands on the ⅛″ marks at 6″, 9″ and 12″, so every piece measures with a ruler at all three. It also cuts cleanly at 4″, 7″, 8″, 10″, 14″, 15″, 16″ and 18″. In Quarter Inch you can make it any size, and it says when a cut falls between the lines.
Can I paper piece it?
Yes. It sews on one paper, its pieces added in order. In Quarter Inch, the Foundations tab prints its papers at true size (with Quilter).
Is it a good block for a beginner?
It’s a first-quilt block: 2 pieces in 1 shape. Nothing in it curves or has to be set in. We work the level out from the block’s own geometry, never by eye.