Starting Square
5"
Beginner cut size for each Fabric A and Fabric B square
- Base starting square
- 4 7/8"
- Trim each HST to
- 4 1/2" unfinished
- Finished in the quilt
- 4"
4-at-a-time HSTs have bias outer edges. Handle them carefully to reduce stretching.
Production & Fabric Plan
- Required
- 40 HSTs
- Batches
- 20
- Produced
- 40 HSTs · 0 extra
- Fabric A
- 20 squares · 3 WOF strips · 1/2 yard
- Fabric B
- 20 squares · 3 WOF strips · 1/2 yard
Each batch uses one Fabric A square and one Fabric B square. Yardage assumes 42" usable width of fabric.
HST Quilt Top Plan
- Grid
- 12 × 15
- Total HSTs
- 180
- Planned top
- 48" × 60"
Plan the Rest of Your Quilt
To carry an HST-only quilt top into the planner, use Grid mode.
Open the Quilt Planner4-at-a-time note: outer edges are on the bias. Handle carefully to reduce stretching.
Each batch uses one Fabric A starting square and one Fabric B starting square. Consider buying 5–10% extra fabric.
Planning estimate only. Yardage assumes 42" usable width and rounds up to 1/4 yard. Follow commercial pattern cutting instructions when provided.
Finished vs. Unfinished HST Size
Finished size is the Half Square Triangle size after it is sewn into the quilt. The unfinished HST is 1/2" larger so it includes seam allowance.
Using a commercial pattern? Follow its cutting instructions first; its method and trimming allowance may differ.
2 vs. 4 vs. 8 at a Time
2 at a time
Flexible for smaller batches. Each pair of starting squares makes 2 HSTs.
4 at a time
Efficient, but the outer edges are on the bias and can stretch. Handle carefully.
8 at a time
Efficient for larger quantities. Each pair of starting squares makes 8 HSTs.
How the Calculation Works
- The calculator recommends a beginner cut size with trimming room.
- Batch count rounds up so you make at least the required number of HSTs.
- Fabric A and Fabric B each need one starting square per batch.
- Yardage uses 42" usable width of fabric and rounds up to the next 1/4 yard.
Trim before assembly: Square each unit to the displayed unfinished size, then sew it into the quilt.
These are planning estimates. Consider buying 5–10% extra fabric for shrinkage, cutting mistakes, or test units.
FAQ
The finished Half Square Triangle size is what shows after the block is sewn into the quilt. The unfinished HST is 1/2" larger because it still includes seam allowance.
This calculator shows a minimum size and a slightly larger beginner cut size. The beginner size leaves practical trimming room before assembly.
The 4-at-a-time construction method places the outer HST edges on the fabric bias. Those edges can stretch, so handle them gently and avoid pulling while pressing or sewing.
No. If you are using a commercial quilt pattern, follow its cutting and construction instructions first. Pattern methods and trimming allowances may differ.
Each batch uses one Fabric A square and one Fabric B square. The calculator fits the beginner cut size across 42" usable width of fabric, calculates WOF strips, and rounds each fabric up to the next 1/4 yard.