Number to words
Spell out a whole number in English words, as a cardinal or an ordinal. Runs entirely on your device, nothing is uploaded.
Number to words converts a whole number into English words, as a cardinal like one, or as an ordinal like first. It covers magnitudes up to a quadrillion by name, refusing anything larger. A negative number gets a leading negative word rather than a separate construction. Decimal numbers are not accepted, since only whole numbers are parsed.
Questions
What is the largest number it can spell out?
under one quadrillion times a thousand, specifically 999,999,999,999,999; anything larger is refused with "number-to-words covers magnitudes up to 10^15".
How does ordinal mode change the output?
It takes the cardinal spelling, such as "twenty-one", and converts only the final word's ending to its ordinal form using a lookup table, giving "twenty-first"; compound endings like -y are converted to -ieth when the exact word is not in the table.
Does it accept decimal numbers?
No. The input must match a plain whole-number pattern, optionally with a leading minus sign; anything with a decimal point is refused as "not a whole number".
How are negative numbers spelled out?
With the word "negative" placed in front of the rest of the spelled-out number, so -42 becomes "negative forty-two".
What happens with a number too large for exact integer math?
It is refused with "number is too large for exact conversion", checked against JavaScript's definition of a safe integer, which catches numbers where floating-point rounding can otherwise silently change the digits.