# Codeword

> A codeword is one 8-bit byte in a QR code's data stream. Capacity tables are ultimately expressed in codewords: a version-1 code holds 26 of them, split between data and error correction.

Source: https://useqr.app/glossary/codeword · Last reviewed 2026-08-21 · UseQR is free forever, MIT licensed, no signup.

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## Data versus error-correction codewords

Every version has a fixed total codeword count. The error-correction level decides how that
total is split.

| Version 1 | Total | Data | Error correction |
|---|---|---|---|
| L | 26 | 19 | 7 |
| M | 26 | 16 | 10 |
| Q | 26 | 13 | 13 |
| H | 26 | 9 | 17 |

At level H, a version-1 code spends nearly two thirds of its capacity on redundancy. That
is the cost of 30% damage tolerance.

## Remainder bits

Some versions have a few leftover bits after the codewords are placed — 7 bits at versions
2–6, for example. They are set to zero and ignored.