QR code size for print: how big a UPI QR needs to be

The rule of thumb: print the QR about one-tenth as wide as the distance it's scanned from, and never smaller than 2.5 cm (1 inch). A counter card read from 30 cm needs a 3 cm code; a wall poster read from a metre needs 10 cm or more. Most printed QR failures come from four things: too small, no margin, a glossy finish, or a low-resolution image scaled up. Fix those and a printed code just works.

Size

About one-tenth of the scanning distance. It's the ratio QR printing guides work to, and it holds from a business card to a hoarding.

There's also a floor. Whatever the ratio suggests, don't print a UPI QR smaller than about 2.5 cm (25 mm, 1 inch) square. Below that, print quality and camera focus matter more than the maths, and a code that scans on your phone at your desk can fail on an older phone in a dim shop.

Round up. Nobody has ever failed to scan a code for being too big.

On ezyupi's templates, the QR prints at about 9–11 cm on the A5 counter standee, 13–15 cm on the A4 poster, 4–6 cm on the square sticker and 3–4 cm on the round one.

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The quiet zone

The blank margin around a QR is part of the code: phone cameras use it to find the edges. The ISO/IEC 18004 standard sets it at at least four modules (the code's small squares) on every side.

Don't let a border, your shop name or a decorative frame run into it, and don't crop the code to fit.

Print from vector

A PNG is pixels. Enlarge it for a poster and the edges go soft, which makes a camera hesitate in poor light.

An SVG is instructions for drawing shapes, so it stays crisp at any size. Use the SVG from the generator for anything a printer touches, or the print templates' PDF. If a printer insists on an image file, give them at least 300 DPI at the final printed size.

Contrast and orientation

Dark code, light background. Cameras expect it, and inverted codes (light on dark) fail on many phones.

If you're colouring it, keep the code properly dark. A mid-grey code on cream looks elegant on screen and scans badly on a dim counter. Test it on an older Android phone, not your own.

How much damage a QR can take

QR codes have error correction built in: part of the pattern can be scuffed, stained or covered and the code still reads. There are four levels:

Higher levels make the code denser, so for the same size each square is smaller. ezyupi uses level M for plain codes and switches to H when you add a logo.

A logo in the middle relies on this. Keep it to about a fifth of the code's width, centred, and test the printed version, not the screen version, before ordering a batch.

A worn code is living on borrowed time. Error correction covers a scuff, not a torn corner and a coffee stain together. When a counter card starts failing, replace it rather than tilting the phone.

Material and finish

Matte, not glossy. Gloss throws a highlight under a tube light, exactly where the phone needs to read.

Laminate for a counter: matte lamination, or a matte acrylic standee. Bare paper near a busy till picks up oil and thumbprints within weeks.

Outdoors, use vinyl with a matte overlaminate. Paper fades and curls in sun and rain.

Print a spare, so a torn card is replaced the same day.

Placement

Chest height for a wall poster or standee. People scan straight on, not by craning upwards.

Facing the customer, with a slight upward tilt on a counter, so the phone doesn't have to be held flat over it.

Away from glare. A tube light directly overhead or afternoon sun through a window can wash out even a matte card. Move it a few centimetres and test again.

Not behind glass or a plastic sleeve. Both reflect. If the QR is in a display case, put a copy outside it.

Clear of clutter. A QR half hidden behind a pen stand or a sweet jar is a QR people give up on.

Put the UPI ID underneath

Print your UPI ID in small text below the code. Phones get old, lenses get scratched, light gets bad, and when the camera gives up, a printed ID means the payment still happens. NPCI's brand guidelines ask merchants to show their UPI ID below the QR, and ezyupi's templates do it for you.

Add the name customers will see on their screen too ("You'll see RAKESH K SHARMA"). It's the quickest way for them to spot a QR that someone has pasted over yours.

Test it properly

1. Scan the on-screen version with two different UPI apps.
2. Print one copy and scan that.
3. Scan it from the distance it'll be used at, in the light it'll be in. A shop counter at 7 pm isn't your desk at noon.
4. Try an older phone, and try at a slight angle.
5. Hand it to someone else to scan on their phone. Their camera isn't yours.

Only then order the batch.

When it won't scan

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