QR Code Encoding Capacity
At maximum size (version 40) and the lowest error correction level, a QR code can hold up to roughly 7,089 numeric digits, 4,296 alphanumeric characters, or 2,953 bytes of binary/text data — but real-world codes for URLs or contact cards use a small fraction of that.
These maximums trade off directly against error correction and print density: pushing more data in means a bigger, more detailed grid, and choosing a higher error correction level (for print reliability) reduces how much data fits at a given version. That's why generators pick the smallest version that fits your content — it keeps the resulting code as simple and scan-friendly as possible.
In practice, a shortened URL might only use a few hundred bytes of that capacity. Long-form content like an entire paragraph of plain text will produce a visibly denser, harder-to-scan-small code — worth keeping in mind before encoding something lengthy.