Data Matrix Generator
Generate an ECC 200 Data Matrix (square, 10 × 10 to 144 × 144) as a clean SVG with your text, module size and colours — in-house encoder, runs in the browser.
A downloadable SVG symbol with its size, region count, codewords used and error-correction codewords, the fill ratio, and the printed size at a module size you enter.
Example: "123456" fits the smallest 10 × 10 symbol as three data codewords (142 164 186) plus five Reed–Solomon codewords — the worked example of the ISO standard; 1,500 characters fill the 144 × 144 symbol.
ECC 200,
built from the standard.
How the data is encoded, how the symbol is laid out, and what the in-house encoder covers.
Encoding
ASCII encodation: two digits become one codeword (130 + the pair), any other ASCII character its value + 1, upper ASCII via the 235 shift; the symbol is padded with 129 and the standard’s randomised pad. Reed–Solomon error-correction codewords are computed over GF(256) with the Data Matrix polynomial, in interleaved blocks for the large symbols. The standard’s own example, 123456, reproduces its five EC codewords exactly (114 25 5 88 102).
Layout
Codewords are placed bit by bit in the L-shaped "utah" pattern of Annex F with its four corner cases, the mapping is split into regions for symbols above 26 modules, and each region is framed by the finder pattern: solid left and bottom edges, dashed top and right. A one-module quiet zone surrounds the symbol.
Scope
Square symbols only (10 × 10 to 144 × 144), ASCII encodation only — always valid, though C40 or Base 256 can be denser for some inputs — and no FNC1 / GS1 mode, rectangular sizes or structured append. Print at a module size your scanner is specified to read. Nothing leaves the browser; the same four anonymous usage counts as the rest of the site apply.
SOURCES
- ISO/IEC 16022:2006 Data Matrix ECC 200: ASCII encodation, Reed–Solomon over GF(256) with polynomial 0x12D, Table 7 symbol attributes, Annex F codeword placement, Annex O worked example (123456)
Last reviewed 20 September 2026. How results are checked: How we verify.