SeamGrid

SeamGrid

Boxy pouch pattern calculator

Enter the finished size you want for the pouch and the seam allowance you plan to sew. The page returns a cut plan for a two-panel boxy pouch, plus a short guide for checking the fit with a test sample.

Calculator

Create your custom cut plan

Enter the finished length, width, height, and seam allowance to compare custom boxy pouch measurements and the resulting boxy pouch sewing pattern at a glance.

Size inputs

Start with the finished size you want, then choose the same unit for every field.

Boxy pouch calculator inputs
in

Enter the finished pouch length.

in

Enter the finished pouch width.

in

Enter the box height from seam to seam.

in

Use the allowance you plan to sew.

Choose inches or centimetres.

Cut plan

Cut plan

Cut plan ready for your boxy pouch sewing pattern.

Sew a quick test sample before cutting your best fabric.

12 × 8 in

Schematic cut planSchematic only. The drawing is for screen guidance. It shows the cut length, cut width, corner mark, and the outer and lining pieces for the current calculator values.OuterLining12 in8 inCorner mark: 2 inOuterLining
Schematic only. The drawing is for screen guidance. It shows the cut length, cut width, corner mark, and the outer and lining pieces for the current calculator values.

Measurements

How to measure

Measure the finished pouch size you want, not the fabric before sewing. Length runs left to right, width runs front to back, and height is the boxed depth from seam to seam.

The seam allowance belongs on every raw edge. The calculator uses the same allowance for the outer and lining rectangles, then turns the height into the corner mark.

The calculator is built for a boxy pouch sewing pattern workflow: give it the finished pouch dimensions first, then compare the resulting boxy pouch measurements against your fabric before you cut.

Finished size guide

Length, width, height, and seam allowance are the four values the calculator needs.

Worked example

Worked example

These are calculated cut plans in imperial and metric units, not measurements taken from a finished sewn sample.

01

Calculated imperial example

Finished size
7 × 3 × 4 in
Seam allowance
0.5 in
Cut plan
four 12 × 8 in rectangles
Corner mark
2 in

02

Calculated metric example

Finished size
20 × 8 × 10 cm
Seam allowance
1 cm
Cut plan
four 32 × 20 cm rectangles
Corner mark
5 cm

How to make

How to make a boxy pouch

This is workflow context for the two-panel boxy pouch sewing pattern. Construction methods vary, and the calculator does not determine zipper-end treatment.

  1. Cut two outer rectangles and two lining rectangles from the calculated sizes.

  2. Mark the boxed corners with the corner mark from the calculator, then transfer the marks to both layers.

  3. Assemble the pouch body using the seam order your method calls for, because zipper-end treatment and lining opening details vary.

  4. Check that the boxy shape and seam allowances still match the finished dimensions you planned.

  5. Finish the pouch, then compare the result against the test sample before using your best fabric.

Assumptions

Assumptions

The calculator assumes one seam allowance for the whole cut plan and a two-panel layout with matching outer and lining pieces.

  • The finished dimensions describe the pouch after sewing, not the cut fabric size.
  • The same seam allowance applies to every raw edge in the cut plan.
  • The outer and lining rectangles share the same cut dimensions.
  • The corner mark is taken from the seam-intersection point and set at half the finished height.
  • The calculator does not choose zipper-end treatment, lining opening placement, or other method-specific details.

Mistakes

Common mistakes

  1. Swapping finished size for cut size.

  2. Using different seam allowances on different edges.

  3. Measuring the corner mark from the wrong starting point.

  4. Forgetting that the outer and lining rectangles must match.

  5. Skipping a test sample before cutting the final fabric.

Formula

Formula

The calculator uses three formulas and one piece count for the two-panel boxy pouch.

  1. cut length = finished length + height + 2 × seam allowance
  2. cut width = finished width + height + 2 × seam allowance
  3. corner mark = height ÷ 2

Test sample

Test sample

Sew a quick test sample before cutting your best fabric. A small sample helps you confirm how your fabric, seam allowance, and finishing method behave together.