Quarter-Square Triangle Calculator
Enter the finished QST or hourglass size and how many you need. Sashing gives you the cut square, the alternative starting size if you prefer building them from two HSTs, and how many squares to cut.
Cut squares
5 1/4"
In the app, this also gives you
- Yardage for both fabrics
- HSTs and flying geese too
- Saved into your project's cut list
What size do I cut for quarter-square triangles?
Cut the square 1 1/4 inch larger than the finished unit, then cut it on both diagonals. The larger addition — where a half-square triangle only needs 7/8" — pays for two bias seam allowances instead of one, and it puts the straight grain of the fabric on the outer edges of the finished unit where it belongs.
Pair one square of each fabric, sew a quarter inch either side of one diagonal, cut on the line, and press: two half-square triangles. Lay those together with opposite fabrics facing and the seams nested, draw a line at right angles across the seam, sew either side and cut again. Two hourglass units.
Prefer to look it up? The quarter-square triangle chartlists every common size, and the HST chart covers its 7/8" cousin.
There's more where that came from
The app adds the yardage for both fabrics, does half-square triangles and flying geese alongside, and saves the cut sizes into your project.
Coming to the App Store for iPhone and iPad.