What size should a QR code be? The distance rule
By Nasir Uddin Shamim · Founder, PrintxPDF
Updated 2026-08-11 · 6 min read
Short answer: Use the 10:1 rule: a QR code must be at least one tenth as wide as the distance it is scanned from. A code read at 30 cm needs to be 3 cm wide; one read from 3 metres needs 30 cm. The absolute floor for any printed code is 2 cm.
There is exactly one number to remember about QR code sizing, and everything else is arithmetic around it.
Minimum code width = scanning distance ÷ 10
That is the 10:1 rule, and it comes from the field of view a typical camera needs to resolve the individual modules. A business card is read from about 20 cm, so the code needs to be 2 cm wide. A poster read from 2 metres needs a 20 cm code. A code on a motorway billboard read from 30 metres needs to be 3 metres across, which is usually the moment a client decides against a billboard QR code.
The size table
| Where it goes | Read from | Minimum width | Recommended width |
|---|---|---|---|
| Business card | 20 cm / 8 in | 20 mm / 0.8 in | 20-25 mm / 0.8-1 in |
| Product label, packaging | 25 cm / 10 in | 25 mm / 1 in | 25-30 mm / 1-1.2 in |
| Flyer, leaflet, brochure | 30 cm / 12 in | 30 mm / 1.2 in | 30-40 mm / 1.2-1.6 in |
| Restaurant menu, table tent | 40-60 cm / 16-24 in | 40 mm / 1.6 in | 40-50 mm / 1.6-2 in |
| A4 wall notice, indoor sign | 1 m / 3 ft | 100 mm / 4 in | 100-120 mm / 4-4.7 in |
| A2 poster at eye level | 1.5 m / 5 ft | 150 mm / 6 in | 150-200 mm / 6-8 in |
| Shop window decal | 2 m / 6.5 ft | 200 mm / 8 in | 250 mm / 10 in |
| Trade show banner | 3 m / 10 ft | 300 mm / 12 in | 350-400 mm / 14-16 in |
| Vehicle wrap | 5 m / 16 ft | 500 mm / 20 in | 600 mm / 24 in |
| Billboard | 30 m / 100 ft | 3 m / 10 ft | Do not use a QR code here |
Typical scanning distances and the minimum QR code width each one demands.
Watch out: The recommended column exists because the 10:1 rule is a floor, not a target. It assumes a steady hand, decent light and a reasonably modern camera. Adding 20 to 30 percent buys you dim restaurants, older phones and people who scan while walking.
Why the rule works: module size
The rule is really about the module, the smallest black or white square in the grid. A camera needs several sensor pixels per module to decode reliably, which in print terms means each module should be at least 0.5 mm wide, and never below 0.4 mm.
How many modules you have depends on how much data you encode. A version 1 symbol is 21 modules square; each version adds four, up to version 40 at 177 modules square. Short payloads make sparse, forgiving codes; long ones make dense, fragile codes.
| What you encode | Roughly | Grid | Width at 0.5 mm modules |
|---|---|---|---|
| Short link, e.g. example.com/x | 15 characters | Version 1, 21 x 21 | 10.5 mm |
| Normal URL | 40 characters | Version 3, 29 x 29 | 14.5 mm |
| URL with tracking parameters | 90 characters | Version 5, 37 x 37 | 18.5 mm |
| WiFi payload with a long password | 60 characters | Version 4, 33 x 33 | 16.5 mm |
| Full vCard with address | 350 characters | Version 11, 61 x 61 | 30.5 mm |
| Long plain text | 1,000 characters | Version 21, 101 x 101 | 50.5 mm |
How payload length drives the grid, at error correction level M.
Read that last row again. A thousand characters of text needs a 50 mm code just to reach the minimum module size, which is why encoding a whole paragraph is a bad idea. Encode a short URL and let the page hold the content. The same logic applies on a card: a link beats a full vCard when space is tight.
Pixels, DPI and what to hand the printer
If you are supplying a raster file rather than vector, the conversion is pixels = millimetres × DPI ÷ 25.4. Commercial print is 300 DPI; large-format banners and vehicle wraps are usually 100 to 150 DPI because nobody stands close to them.
| Printed width | At 300 DPI | At 600 DPI | At 150 DPI (large format) |
|---|---|---|---|
| 20 mm | 236 px | 472 px | 118 px |
| 30 mm | 354 px | 709 px | 177 px |
| 50 mm | 591 px | 1,181 px | 295 px |
| 100 mm | 1,181 px | 2,362 px | 591 px |
| 200 mm | 2,362 px | 4,724 px | 1,181 px |
| 500 mm | 5,906 px | 11,811 px | 2,953 px |
Pixel dimensions needed for a given printed size.
Note: Every number in that table becomes irrelevant if you export SVG, which is why the QR code generator offers it first. Use the pixel table only when a system refuses vector, such as a template that accepts PNG uploads only.
Working out your own size
- Measure the real scanning distance Not the distance you imagine. Stand where a customer stands, hold a phone the way a customer holds it, and measure.
- Divide by ten That is your absolute minimum symbol width, excluding the quiet zone.
- Add 25 percent This is your working size. It covers poor light, older cameras and scanning at an angle.
- Add the quiet zone Four blank modules on each side. On a 40 mm code that is roughly 5 mm of clear space all round, so reserve 50 mm in the layout.
- Check the module size Divide your working width by the grid size. If the answer is under 0.5 mm, shorten the payload or make the code bigger.
- Proof at final size Print one, scan it at the real distance with an old phone, then commit. The full checklist is in making a QR code that scans.
Generate a code at any size as SVG, PNG or a print-ready PDF, free and in your browser.
Angle, motion and light
The 10:1 rule assumes the phone is held roughly square to the code. Decoding degrades past about 30 degrees of tilt, so a code on a sloped table tent or a shelf edge should be sized as if it were 20 to 30 percent further away. Anything scanned in motion, on an escalator or from a bus, needs to be larger still, and codes on moving vehicles do not work at all. Codes people scan while seated, such as a WiFi card on a table, are the easy case.
Frequently asked questions
What is the minimum size for a QR code?
Twenty millimetres, about 0.8 inches, for anything held in the hand. Below that, individual modules fall under the 0.4 mm that consumer printing and phone cameras can resolve, and scan success drops sharply even in good light.
What is the 10:1 rule for QR codes?
The code must be at least one tenth as wide as the distance it is scanned from. Scanned at 30 cm, it needs to be 3 cm wide. Scanned at 3 metres, 30 cm wide. Add another 25 percent for real-world lighting and older phones.
What DPI should a printed QR code be?
Three hundred DPI for standard commercial printing, and 100 to 150 DPI for large-format banners viewed from a distance. Vector SVG sidesteps the question entirely, because it has no fixed resolution and prints sharp at any size.
Does a longer URL make the QR code bigger?
It makes it denser, not automatically bigger. More characters mean more modules in the same square, so each module shrinks. To keep modules above 0.5 mm you must either enlarge the code or shorten the URL, and shortening is usually easier.
Do QR codes work on billboards?
Rarely. At a 30 metre viewing distance the rule demands a 3 metre code, and drivers cannot safely scan anything anyway. Use a short, memorable URL on a billboard and save QR codes for print people can hold still.