Spell numbers out in English — cardinal (one hundred twenty-three), ordinal (one hundred twenty-third), currency (cheque format), or a mix. Switch between US short-scale (billion = 109) and UK / European long-scale (billion = 1012). Supports negatives, decimals, fractions, and arbitrarily large integers via BigInt.
| Form | Output |
|---|---|
| Negative spoken | |
| Ordinal short | |
| Roman (≤ 3999) | |
| Hex / Bin (int) | |
| Sci notation |
Integers are parsed with BigInt, so arbitrarily large whole numbers spell out cleanly. Word names are filled in up to 1066 (vigintillion in short scale, decilliard in long scale); anything bigger is reported as a sum of named groups. The fractional part is spelled digit-by-digit (point one four one five…) to avoid the ambiguity of "fifty-eight thousandths" vs "five hundred eight ten-thousandths". 1/3, 3 1/2, and percentages like 12.5% are accepted too.