QR Tag & Keyring

A printable QR code for a link, a menu, a wedding album or a business card.

Generated in your browser — the link is never sent anywhere.

1 What it points to

Link or text A full URL including https:// scans most reliably. Error correction Higher survives scratches and dirt better, but needs more modules in the same space.

Scan the preview above with your phone before printing. If it will not read on screen, it will not read in plastic.

2 The tag

Size The QR square, including its required clear border. mm Base thickness The backing plate. Also the height to change filament at. mm Relief height How far the dark modules stand proud of the base. mm Keyhole wall hanger A round opening with a slot, so the tag drops over a screw head and sits flat on the wall. Hanging hole 0 for none. 4 mm suits a split ring. mm Screw head The round part. Measure the head and add about 1 mm. mm Screw shank The slot width. Must be narrower than the head. mm Slot length How far the tag slides down onto the screw. mm Hole position Nozzle Used to check the modules are big enough to print. mm Label text Optional. Raised the same height as the code, on the same plate. Label position Label height Height of the letters. Shrinks automatically if it would be wider than the code. mm Label font Bold label Bold survives printing far better at small sizes.

Getting a printed QR to actually scan

Contrast beats relief. A scanner reads light and dark, not height. The single most effective thing you can do is a filament change at the top of the base plate — light base plate, dark modules. The exact Z is shown above.
Give each module room. Below about two extrusion widths per module the printer smears the pattern and no amount of error correction saves it. The warning above is based on the code that was actually generated, which changes with the length of your link.
Shorter links make easier codes. A URL shortener can drop the code two or three versions, which means noticeably bigger modules on the same size tag.
Do not skip the clear border. It is part of the specification, and it is already included in the size shown — do not trim the tag down to the pattern.
A label is not a substitute for the clear border. Text is placed a full quiet zone away from the code, and the code keeps its border whether or not you add one — that gap is what the scanner needs, so do not close it up in a slicer.
Keep labels bold and short. The label is capped to the width of the code, so a long phrase shrinks itself rather than widening the tag. If it comes out too small to read, shorten the text rather than raising the height.
The keyhole hangs the tag, so mind which edge it is on. The slot always points in towards the middle of the plate, because that is the way the tag travels as you drop it onto the screw — the shank ends up at the far end of the slot taking the weight. Put it on the top edge unless you have a reason not to.
Test before you print a batch. Scan the on-screen preview, then scan the first one off the printer under the lighting where it will actually be used.

Make a 3D-printed QR code tag

Make a printable QR code for a link, a menu, a wedding album or a business card: as a keyring with a hanging hole, a tag with a keyhole to hang on a screw, or a small sign with an optional label. Set the size, the base thickness and how far the code stands proud.

Scan the preview with your phone before you print. The page warns you if the squares are too small for your nozzle, and the link is never sent anywhere: the code is generated in your browser.

Frequently asked questions

Will a 3D-printed QR code scan?

Yes, when there is enough contrast. A scanner reads light and dark, not height, so change filament at the top of the base plate: a light base with dark squares. The page shows the exact height.

How big should a QR code tag be?

Big enough for each square to be at least about two extrusion widths. Longer links make denser codes, so a shorter link lets the same tag have bigger squares.

Can I trim the white border?

No. The clear border is part of the QR standard and scanners need it; it is already included in the size.

Can I add text under the code?

Yes. A short bold label prints best; it is kept a full border away from the code so it does not stop it scanning.