Create Custom List

Ten total: {n} decimal number, {0n} always-padded number, {upper}/{col} Excel-style column letters (A, B, …, Z, AA, AB, …), {lower} lowercase column letters, {roman} Roman numerals (I-MMMCMXCIX, 1-3999 supported), {hex}/{HEX} lowercase/uppercase hexadecimal, {bin} binary, {oct} octal. Multiple in one pattern is fine – they all use the same iteration number.

Synced. Both reflect the current iteration number. {n}. {upper}-{lower} at i=27 = “27. AA-aa”. If you want independent counters, generate two lists and merge – this tool is single-counter by design.

Excel-style continuation (AA, AB, …, AZ, BA, …, ZZ, AAA, …) gives unique labels for any iteration count. If you genuinely want simple A-Z wrap, use {HEX} or write the modular math yourself.

{n} is the raw number, padded only if you set the zero-padding input > 0. {0n} is always padded by the zero-padding setting (or shows raw number if padding is 0). Useful when you want some placeholders padded and others not in the same pattern.

Standard Roman numerals don’t have a clean way to represent 4000+. The largest standard symbol is M (1000), with subtractive pairs going up to MMMCMXCIX = 3999. Beyond that requires overlines or apostrophes that don’t render in plain text. The tool emits a sentinel so you notice the limit instead of silently producing wrong output.

One item per row, one column. Items containing commas, quotes, or newlines are wrapped in double-quotes and internal quotes are doubled per RFC 4180. Optional header row available. For multi-column data, run the tool twice with different patterns and merge in your spreadsheet.

The tool runs synchronously on the main thread. Above 10k items, the UI can stutter on lower-end devices and the textarea becomes slow to render. For larger needs, copy the pattern + range and run it in your own script (Python, Node, etc).

Yes. Set start > end and step < 0. Negative numbers in {n} render with the minus sign; in {hex}/{bin}/{oct} they use JavaScript’s toString(radix) convention (a leading “-“). {roman} for non-positive returns the >3999 sentinel.

Ctrl+Enter (Cmd+Enter on Mac) triggers Generate from anywhere on the page – you don’t need to click the button. Works in all the input fields too.

No. Pure browser-side JavaScript. Your patterns and outputs never leave the page.