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
SeamGrid
Boxy pouch pattern calculator
Enter your finished pouch size and seam allowance to calculate two outer and two lining rectangles, plus the corner mark. For a two-panel lined pouch; not physically validated. Make a test sample first.
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.
Cut plan
Cut plan
Sew a quick test sample before cutting your best fabric.
12 in × 8 in
- Outer pieces
- Lining pieces
- Cut length
- Cut width
- Corner mark
- Result unit
How to measure
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.
Plan four rectangles at the calculated size: two outer and two lining, not one larger piece cut in half. This is not the one-panel French-seam method; check your construction before cutting.
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
Worked example
These are calculated cut plans in imperial and metric units, not measurements taken from a finished sewn sample.
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 a boxy pouch
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.
Cut two outer rectangles and two lining rectangles from the calculated sizes.
Mark the boxed corners with the corner mark from the calculator, then transfer the marks to both layers.
Assemble the pouch body using the seam order your method calls for, because zipper-end treatment and lining opening details vary.
Check that the boxy shape and seam allowances still match the finished dimensions you planned.
Finish the pouch, then compare the result against the test sample before using your best fabric.
Assumptions
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.
Common mistakes
Mistakes
Common mistakes
Swapping finished size for cut size.
Using different seam allowances on different edges.
Measuring the corner mark from the wrong starting point.
Forgetting that the outer and lining rectangles must match.
Skipping a test sample before cutting the final fabric.
Formula
Formula
Formula
The calculator uses three formulas and one piece count for the two-panel boxy pouch.
- cut length = finished length + height + 2 × seam allowance
- cut width = finished width + height + 2 × seam allowance
- corner mark = height ÷ 2
Test sample
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.