Spell out any whole number in English words — for checks, contracts, and forms.
Handles whole numbers into the billions, using standard American English (no "and" after hundred: 105 is "one hundred five"). This is the wording used when writing amounts on checks and in legal documents, where the written form is the one that counts.
How do I write a check amount? Write the dollars in words on the line ("One hundred twenty-three") and the cents as a fraction: "and 45/100". The words control if they disagree with the digits.
Does it handle decimals? Whole numbers only — spell the part after the decimal separately as cents or as "point" digits.