How Much Data Can a QR Code Hold? Versions, Modes and Limits
How much data can a QR code hold? A web address, a contact card, a Wi-Fi password, but what's the real limit?
QR codes come in 40 versions, from 21×21 modules up to 177×177, growing by four modules each step. Data is packed in one of four modes (numeric, alphanumeric, byte and kanji), each fitting a different number of bits per character. The record is version 40 at level L: 7,089 digits, 4,296 letters and numbers, or 2,953 bytes. But error correction takes its share, and at level H repair data fills most of the code. More data also means smaller modules at the same printed size, so dense codes need printing bigger. The practical answer: keep the link short, and let a short link do the rest. We also cover structured append, which splits data across up to 16 codes.
One little square can hold a web address, a contact card, or more than 7,000 digits.
So how much can a QR code really hold?
It starts with the version.
QR codes come in 40 sizes, numbered 1 to 40.
Version 1 is 21 by 21 modules.
Each version adds 4 more on every side.
So version 40 is 177 across.
From version 7, two small blocks even spell out the version number.
Then packing, a QR code has four modes.
Numeric mode fits three digits into 10 bits.
Alphanumeric covers capital letters, digits, and a few symbols.
Two characters in 11 bits.
Byte mode takes anything, eight bits at a time.
Kanji mode packs Japanese characters, 13 bits each.
So the same address in capitals can make a smaller code than in lowercase.
The record, version 40 at the lowest error correction holds 7,089 digits, 4,296 capitals, 2,953 bytes, or 1,817 kanji.
But error correction takes its share.
At level H, repair data fills most of the code.
So the same code holds just 1,273 bytes.
And more data has a cost.
At the same printed size, a higher version means smaller modules.
So as in episode 5, it needs a bigger print, and it fails sooner in poor light.
Most short web links sit in versions 2 to 5.
So keep it short.
A long link full of tracking tags makes a dense code.
A short link stays small, however big the page behind it.
Data that won't fit can be split across up to 16 codes, but few phone cameras join them back up.
So, what's the most a QR code can hold?
Up to 7,089 digits, but the best codes hold far less.
Keep the link short and spend the space on how it looks.
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Keep the link short, and spend the space on how it looks.
