Sizing cards
← HomeA sizing card (also called a calibration card) is how PatternForge learns the real-world size of your pattern. Print one at 100% / Actual Size, lay it flat next to your pattern, and photograph them together. Generation: rev 2 · 2025.
Printing — avoid “Fit to Page”
- Open the PDF for your paper size below.
- In the print dialog choose Actual Size / 100%. Turn off“Fit to Page”, “Shrink to Fit”, or “Scale to Fit”.
- After printing, measure the verification linewith a ruler. It must read the exact length shown on the sheet. If it's off, your printer rescaled it — fix the scaling and reprint.
Plain paper is fine. Mounting the printed sheet to cardstock or foam board keeps it flat and improves accuracy.
US Letter sizing card
Page 215.9 × 279.4 mm · verification line 8.000 in (203.2 mm)
PF-USLETTER-CHARUCO-001 · rev 2
How to measure: lay a ruler along the labelled verification line on the printed sheet. End to end it must equal 8.000 in. The printed sheet also carries these instructions so you can verify it away from the computer.
A4 sizing card
Page 210 × 297 mm · verification line 200 mm (7.874 in)
PF-A4-CHARUCO-001 · rev 2
How to measure: lay a ruler along the labelled verification line on the printed sheet. End to end it must equal 200 mm. The printed sheet also carries these instructions so you can verify it away from the computer.