How much data can a QR code hold?

The theoretical max is 7,089 numeric digits, 4,296 alphanumeric characters, or 2,953 bytes (at version 40 with the lowest error correction). In practice, almost nobody uses anything that big. Most printed QRs are versions 5 to 15.

What are QR code versions?

QR codes come in 40 sizes called versions. Version 1 is 21 modules wide, version 40 is 177 modules wide. Each version up adds 4 modules per side. Higher versions hold more data but need more space or higher print resolution.

What are error correction levels?

QR codes use Reed-Solomon error correction so they survive partial damage. Four levels: L recovers about 7%, M about 15%, Q about 25%, H about 30%. Higher recovery costs you data capacity at the same version.

What's the difference between numeric, alphanumeric, byte, and Kanji modes?

QR codes have four encoding modes. Numeric (digits only) packs the most. Alphanumeric (digits, uppercase letters, a few symbols) is less efficient. Byte mode (full 8-bit) is the most flexible but the least dense. Kanji mode is optimized for Japanese. If your content fits a narrower mode, you'll get more in fewer modules.

Which error correction level should I use?

M is the usual default. Use Q or H if your code will get scuffed, partially obscured, or you want to drop a logo over the center. Only use L when capacity is tight and you're sure the print will be clean.

QR Code Capacity Calculator

Paste your data. We tell you the smallest QR version that fits it, the module count, and how much room you have left at each error correction level. All 40 versions, all 4 EC levels, live.

Paste or type the data you want to encode

Characters

Detected mode

—

Required QR version by error correction level

Live preview (EC level M)

Reference: max capacity by version (EC level M)

Version	Modules	Numeric	Alphanumeric	Bytes
v1	21×21	34	20	14
v2	25×25	63	38	26
v3	29×29	101	61	42
v4	33×33	149	90	62
v5	37×37	202	122	84
v10	57×57	513	311	213
v15	77×77	991	600	412
v20	97×97	1531	927	636
v25	117×117	2089	1265	868
v30	137×137	2812	1704	1170
v35	157×157	3417	2071	1422
v40	177×177	5596	3391	2331

"Modules" is the side length in squares. Capacities shown for EC level M (~15% recovery). L is higher, Q and H lower. Source: ISO/IEC 18004.

How QR code capacity works

A QR's version is its size in modules (the little squares). Version 1 is 21×21. Each version up adds 4 modules per side: v2 is 25, v3 is 29, on up to v40 at 177×177. Higher versions hold more data, but the trade-off is that each module shrinks at the same printed size.

Encoding modes

QR packs bits differently depending on what you're encoding. Numeric mode uses 10 bits per 3 digits, which is genuinely efficient. Alphanumeric (digits, uppercase, a handful of symbols) uses 11 bits per 2 characters. Byte mode handles anything but spends 8 bits per character. If your content is all digits or all uppercase, you'll fit a lot more in the same version.

Error correction levels

QR codes use Reed-Solomon error correction so they keep scanning when damaged. There are four levels:

L: about 7% recovery.
M: about 15%. The usual default.
Q: about 25%. Good for codes that will get scuffed.
H: about 30%. What you need if you want a logo dropped in the middle.

Higher recovery costs you data capacity. Going from L to H roughly halves what you can fit.

Frequently Asked Questions

How much data fits in a QR?: Up to ~7,000 numeric digits or ~3,000 bytes at the largest version, but real-world codes are much smaller. Most live in the v5 to v15 range.
What are QR code versions?: The size, in modules. v1 is 21×21, v40 is 177×177. Each version up adds 4 modules per side.
What are error correction levels?: L recovers ~7% of damage, M ~15%, Q ~25%, H ~30%. Higher recovery, lower capacity.
What's the difference between encoding modes?: Numeric is most efficient, alphanumeric less so, byte handles anything but takes more bits. Kanji is for Japanese.
Which EC level should I use?: M is the default. Use Q or H for codes that will get scuffed or carry a logo. Only use L when you really need the capacity.
Does more data make my QR harder to scan?: Yes, indirectly. More data needs a higher version, which means smaller modules at the same printed size. Print bigger or use a shorter URL.