The largest QR code holds about 7,089 digits, 4,296 uppercase alphanumeric characters, or roughly 3 KB of arbitrary text. Those are ceilings from the standard, not targets. A code at that size is 177 squares across, needs to be printed large and scanned close up, and will frustrate people with older phones. For anything you’ll actually print, treat a few hundred characters as the sensible upper bound and a short link as the ideal.
The maximum a QR code can hold #
Capacity depends on three things at once: the size of the code, the error correction level, and what kind of characters you’re storing. These are the figures for the biggest code, version 40, at the lowest error correction level:
| Character type | Maximum |
|---|---|
| Digits only | 7,089 |
| Uppercase letters, digits and nine symbols | 4,296 |
| Any text, byte by byte | 2,953 bytes |
| Kanji | 1,817 |
Denso Wave, which developed the format, states the 7,089 numerals figure and describes the overall ceiling as about 3 KB or less at version 40 with error correction level L. Its version tables list the capacity of all 40 sizes at each correction level.
Numbers fit better than letters because the encoding packs three digits into ten bits. The alphanumeric mode handles uppercase letters, digits, a space and eight symbols at about 5.5 bits per character. Everything else, including lowercase letters, falls into byte mode at 8 bits per character, and accented letters or emoji eat two to four bytes each.
Why you’ll never use the maximum #
A QR code grows by adding squares, not by getting physically bigger. Version 1 is 21 squares across; version 40 is 177. Print both at the same width and the second one’s squares are eight times narrower.
That causes three problems:
- Cameras lose the detail. Each square needs to land on enough camera pixels to be read. Phone cameras manage this fine at a normal reading distance with a normal code, and fail on a dense one photographed from across a room.
- Printing blurs the edges. Ink spread, cheap paper, curved surfaces and small labels all smear the boundary between squares.
- Older and cheaper scanners give up first. Your new phone is not the test that matters if customers are using five-year-old ones.
Denso Wave’s own sizing guidance works from the module size upward: you decide how small a single square can be for your printing method and scanning distance, then multiply by the grid plus the four-module margin. More data means either a bigger printed code or smaller, riskier squares.
How much do you actually need? #
| What you’re encoding | Typical length | What it does to the code |
|---|---|---|
Short link, https://ex.co/menu | 20 to 30 characters | Small, chunky, scans from a distance |
| Wi-Fi network and password | 40 to 70 characters | Still comfortable on a table card |
| Ordinary web address with a tracking tag | 80 to 150 characters | Noticeably denser, fine on paper up close |
| Contact card with name, phone, email, company, website | 150 to 300 characters | Dense. Print it at least an inch across |
| A paragraph of plain text | 400 characters and up | Needs a large print size or a screen |
A useful rule: if the squares look like fine grain rather than blocks, you’re asking too much of the code.
What changes the capacity #
The error correction level #
The four levels reserve space for recovery data, and that space comes out of your content. Going from level L to level H costs you more than half the capacity of a given code size. Level M is the usual default and the one QR Handler generates at. Our guide to QR code error correction levels covers when to pay for more.
The character mode #
Uppercase-only content, such as a ticket reference like ABC-4471, encodes in the compact alphanumeric mode. The same text in lowercase falls back to byte mode and takes noticeably more room. If you control the format of a reference code, uppercase it.
The version #
Generators pick the smallest version that fits your content at your chosen error correction level, so you don’t choose this directly. You only feel it as the code getting busier when you add more text.
How to fit more into a QR code #
- Shorten the link. A path like
yoursite.com/qron your own domain is the cleanest fix, and it stays under your control. A third-party shortener also shrinks the code, but it hides the destination from everyone who scans it, which is exactly the pattern scam codes rely on. - Trim the contact card. A vCard with a job title, fax number, postal address and photo is a dense code that half your audience can’t read. Name, phone, email and website is usually enough. See what a vCard QR code is.
- Drop the tracking parameters. Long campaign tags can double the length of a URL. Use a short redirect and log the visit on your own site.
- Avoid emoji and accented characters in codes that need to stay small, since each one costs several bytes.
- Don’t raise the error correction level out of habit. Level H is for logos and rough conditions, not for a menu card.
- Link to the file instead of the content. A QR code can’t carry an image, a PDF, a video or an app. Any code that seems to is holding a link to one.
QR Handler creates codes on your phone for links, text, Wi-Fi, contacts, email, phone and SMS, and shows the finished code full-screen and bright, which is the easiest way to test whether a dense code still reads from arm’s length before you print it. Codes are static, so what you type is what the code carries, with no service in between.
When the code is too dense to scan #
If you’ve already printed something and people report failures, the content length is one of several suspects. Contrast, the blank margin and the print size matter just as much. Work through QR code not scanning before you reprint, and test any replacement on at least two different phones from the distance people will really use.
Frequently asked questions #
How many characters can a QR code hold? #
Up to 4,296 uppercase alphanumeric characters, or 2,953 bytes of ordinary text, at the largest size and lowest error correction level. Most codes hold under 300 characters, because denser codes get harder to scan.
What is the maximum URL length for a QR code? #
Technically a link can run to a couple of thousand characters, but a code that long is dense and slow to read. Keep web addresses under about 100 characters, and use a short path on your own domain if you need to.
Can a QR code contain an image, a PDF or a video? #
No. A QR code holds text, and roughly 3 KB of it at most. Codes that appear to open a video or a menu contain a link to a file hosted somewhere else. That also means the file can be changed or taken down without touching the code.
Does more data make a QR code bigger? #
It makes it denser rather than physically larger. The generator adds more squares to the same grid, so each square gets smaller at a fixed print size. Past a point you have to print the code larger to keep it readable.
Is there a limit on Wi-Fi QR codes? #
Only the general one, and no ordinary network comes close. The network name, security type and password together run to a few dozen characters. Very long passphrases with unusual symbols add a little more. Making a Wi-Fi QR code covers the format.