Numeric Mode

Numeric Mode is the most data-efficient of the four QR code encoding modes. It handles only the digits 0 through 9, but compresses three digits into just 10 bits, allowing a single QR code to store up to 7,089 digits at maximum capacity.

The compression works by splitting the input into groups of three digits, converting each group to a 10-bit binary number. A remaining two-digit group uses 7 bits, and a single remaining digit uses 4 bits. For example, "01234567" splits into "012" (10 bits), "345" (10 bits), and "67" (7 bits), totaling 27 bits.

Phone numbers, postal codes, membership IDs, and serial numbers are automatically encoded in Numeric Mode. Using Alphanumeric Mode for the same data would require roughly 1.7 times more bits. QR code generators typically auto-select the optimal mode, but understanding this helps you keep QR codes as compact as possible.