Choose the paper
Pick the paper your print shop uses. A 10 × 15 cm or 4 × 6 in sheet costs little at a photo kiosk. An A4 PDF suits a home printer.
Turn off scaling
Order at 100% scale. Turn off fit to page, borders and auto-crop. Scaling changes the size of each photo.
Measure
Measure one printed photo with a ruler before cutting. It should match the document size to within 0.5 mm.
Cut
Cut along the thin lines between the photos.