Two-at-a-time HST cut plan

Plan paired starting squares for half-square triangle units with the standard two-at-a-time sizing method.

Measurements

Editable example inputs. Adjust them for your project.

Standard two-at-a-time method; assumes a 1/4 in seam allowance. Yardage is not calculated.

Input guidance and units

Enter the finished HST side in inches and the number of units needed.

Enter fractional inches as decimals: 1/8 = 0.125, 1/4 = 0.25, 1/2 = 0.5. Dimensions and yard increments use steps of 0.125; counts use whole numbers. Fraction text such as 1/8 is not accepted in number fields.

What this calculator answers

The two-at-a-time HST method starts from paired squares. The sizing rule and trim target on this page apply to that named construction.

How to use it

  1. Enter the finished HST side after it is sewn into the quilt.
  2. Enter how many finished units are required.
  3. Cut the displayed number of square pairs and trim the sewn units to the unfinished target.

Formula and variables

Starting square side = finished HST side + 7/8 in. Square pairs = ceiling(required units ÷ 2). Unfinished trim target = finished side + 1/2 in.

Finished sidein
HST side after joining into the project.
Starting squarein
Square side before sewing the two-at-a-time diagonal seams.
Unfinished trim targetin
Unit size before it is joined to neighboring pieces.

Independent example

Nine HSTs with a 4 in finished side using the two-at-a-time method.

Each starting square is 4 + 7/8 = 4 7/8 in. ceiling(9 ÷ 2) = 5 pairs, yielding 10 units and one extra. Trim unfinished units to 4 + 1/2 = 4.5 in.

  • 4.875 in starting squares
  • 5 pairs
  • 10 units produced
  • 4.5 in unfinished trim target

What the result means

The extra unit comes from whole paired batches. Yardage and other HST constructions are outside this calculator.

Common questions

Can I use this size rule for every HST method?

No. The inputs and +7/8 in start are for the named two-at-a-time method.

What does unfinished trim size mean?

It is the square size before the unit is sewn into the surrounding quilt.

Method notes and unresolved issues

Use measured usable dimensions and the construction method named on this page. Example inputs are optional and are not universal standards.