How to write a check amount in words
A US check has two amount fields: the small box for numerals (1,234.56) and the long line for words. Banks treat the written words as the legal amount if the two disagree, so the words matter. Write the dollars in words, then the cents as a fraction of 100: "One thousand two hundred thirty-four and 56/100." The word "Dollars" is preprinted at the end of the line, so you do not add it yourself. For a whole-dollar amount write "and 00/100" or "and no/100". Then draw a horizontal line through the empty space so nobody can squeeze in extra words.
The converter produces that exact check format, plus the same amount in other styles you may need for contracts, invoices, promissory notes, wedding invitations and legal documents. Copy any row with one click.
Style rules for numbers in words
American English uses the short scale: thousand, million, billion (10^9), trillion (10^12). Hyphenate compound numbers from twenty-one to ninety-nine, including inside larger numbers: two hundred thirty-four, not two hundred and thirty-four. The "and" is reserved for the decimal point or the cents in US usage, which is why the check style says "and 56/100"; British style puts "and" after hundreds. Do not put commas between groups in words unless a style guide asks for it.
Decimals in plain speech are read digit by digit after the point: 3.14 is "three point one four", not "three point fourteen". Money is read in dollars and cents: $1,234.56 is "one thousand two hundred thirty-four dollars and fifty-six cents". Ordinals change only the last word: 1,234 becomes one thousand two hundred thirty-fourth (1,234th), 20 becomes twentieth, 12 becomes twelfth, and 101 becomes one hundred first.
Worked examples and limits
$0.75 on a check is "Zero and 75/100" (some people write "Only 75/100"). $100 is "One hundred and 00/100". $2,500,000 is "Two million five hundred thousand and 00/100". A contract might say "the sum of Two Million Five Hundred Thousand Dollars ($2,500,000.00)", which is the Title Case row plus the numerals in parentheses, a belt-and-suspenders habit lawyers use so a typo in one form is caught by the other.
The tool accepts dollar signs, commas and spaces, handles negative numbers (written as "negative" for plain words and "minus" for currency, since a check cannot be negative), reads up to ten decimal places in plain words, rounds to the nearest cent for the check and currency lines, and supports whole numbers up to 999,999,999,999,999 (just under one quadrillion). Nothing is sent to a server; the conversion runs in your browser.