How to Write Numbers as Words (Checks & Legal Docs)

Knowing when to spell out a number and when to use digits is one of those skills that matters more than people realize. Write a check incorrectly and the bank may reject it. Use the wrong format in a legal contract and you create ambiguity that could cost thousands. Follow the wrong style guide rule in a published article and your editor sends it back.

This guide covers the rules for writing numbers as words across different contexts: check writing, legal documents, formal prose, and major style guides. For instant conversion of any number to its written form, use our Free Number to Words Converter.

When to Spell Out Numbers vs. Use Digits

Different style guides have different rules, but a general consensus exists across most of them:

Rule	Example
Spell out one through nine	”She adopted three dogs.”
Use digits for 10 and above	”The office has 12 employees.”
Spell out numbers starting a sentence	”Forty-seven people attended.”
Use digits for dates, addresses, times	”Meet at 3:00 PM on March 5.”
Use digits for measurements and data	”The board is 8 feet long.”
Spell out round large numbers	”About two million viewers tuned in.”
Use digits for exact large numbers	”The budget is $2,347,891.”
Use digits for percentages	”Sales increased by 15%.”

Style Guide Differences

AP Style (journalism): Spell out one through nine. Use digits for 10 and above. Always use digits for ages, dimensions, and dollar amounts over a dollar.

Chicago Manual of Style (books, academic): Spell out zero through one hundred, plus round multiples of hundred and thousand (“two hundred,” “forty-five thousand”). Use digits for 101, 102, etc.

APA Style (research papers): Spell out numbers below 10. Use digits for 10 and above. Always use digits in the abstract.

MLA Style (humanities): Spell out numbers that can be written in one or two words (“three,” “ninety-nine,” “fifteen hundred”). Use digits for others (“1,278”).

The takeaway: know which style guide your audience expects and follow it consistently. Mixing rules within the same document looks sloppy.

How to Write Numbers on Checks

Check writing is the most common real-world situation where numbers must be spelled out correctly. Banks compare the written-out amount to the numeric amount in the box, and if they conflict, the written-out version takes legal priority.

Format

The written amount goes on the line that typically says “Pay to the order of” below it or starts with a dollar amount line. Here is the structure:

Amount: $1,245.67

Written: One thousand two hundred forty-five and 67/100

Rules for Check Writing

Start with a capital letter at the beginning of the line.
Use “and” only for the decimal point. Do not write “one hundred and twenty”—write “one hundred twenty.” The word “and” signals the cents.
Write cents as a fraction over 100. Even amounts get “00/100” or “no/100.”
Draw a line after the written amount to fill any remaining space, preventing someone from adding words to inflate the amount.
No dollar sign in the written portion. The line already implies dollars.

Worked Examples

Amount	Written Form
$50.00	Fifty and 00/100 ————————
$123.45	One hundred twenty-three and 45/100 ———
$1,000.00	One thousand and 00/100 —————————
$2,500.75	Two thousand five hundred and 75/100 ——
$10,312.09	Ten thousand three hundred twelve and 09/100
$87.50	Eighty-seven and 50/100 ————————

Common check writing mistakes:

Writing “and” between hundreds and tens (“two hundred and fifty” instead of “two hundred fifty”)—this implies a decimal, creating ambiguity.
Forgetting to draw the line after the amount, leaving space for fraud.
Writing ”$” before the word amount (redundant—it goes in the numeric box only).

Numbers in Legal Documents

Legal contracts use a belt-and-suspenders approach: write the number in words, then repeat it as a digit in parentheses. If the two conflict, courts generally treat the written-out version as the authoritative one.

Format: The Tenant shall pay rent of two thousand five hundred dollars ($2,500.00) per month.

Legal Writing Conventions

Always duplicate: Spell out the number, then put the numeral in parentheses.
Include “.00” for whole dollar amounts to prevent tampering: $2,500.00 not $2,500.
Use “dollars” as a word, not the $ symbol, in the spelled-out portion.
Be explicit about time periods: “thirty (30) calendar days” not “30 days.”
For large sums, include both: “one million two hundred fifty thousand dollars ($1,250,000.00).”

Ambiguity in legal documents can trigger lawsuits. Writing “five hundred” when you mean “five thousand” is an expensive typo. Use our Number to Words Converter to double-check your spelling for high-stakes documents.

Large Number Names

English uses a naming system where each new name represents a factor of 1,000 above the previous one:

Name	Digits	Zeros	Written
Thousand	1,000	3	One thousand
Million	1,000,000	6	One million
Billion	1,000,000,000	9	One billion
Trillion	1,000,000,000,000	12	One trillion
Quadrillion	10^15	15	One quadrillion
Quintillion	10^18	18	One quintillion

US vs. UK naming: The US and UK now use the same system (the “short scale”), where a billion is 10^9. Historically, the UK used the “long scale” where a billion meant 10^12 (a million million). This older usage has mostly died out in British English but persists in some European languages. In French, “un milliard” = 10^9 (one billion), while “un billion” = 10^12.

How to Read Large Numbers Aloud

Break numbers into groups of three digits (thousands, millions, billions) and read each group:

4,738,291 = “four million, seven hundred thirty-eight thousand, two hundred ninety-one”

$12,045,600.00 = “twelve million, forty-five thousand, six hundred dollars”

1,000,000,000 = “one billion” (not “one thousand million,” though both are technically correct)

Compound Numbers and Hyphens

Numbers between twenty-one and ninety-nine are hyphenated when spelled out. This rule applies whether the number stands alone or is part of a larger number.

Twenty-one, thirty-five, forty-eight, sixty-seven, ninety-nine
One hundred twenty-three (hyphen in twenty-three, none after hundred)
Five thousand sixty-two (no hyphen in “five thousand,” hyphen only in compound two-digit numbers if applicable—but sixty-two has it)

Numbers above one hundred don’t get hyphens between the hundreds and the rest: “three hundred fifty-four,” not “three-hundred-fifty-four.”

Ordinal Numbers

Ordinal numbers indicate position or order: first, second, third, fourth, and so on.

Cardinal	Ordinal (word)	Ordinal (abbrev.)
1	first	1st
2	second	2nd
3	third	3rd
4	fourth	4th
5	fifth	5th
9	ninth	9th
12	twelfth	12th
20	twentieth	20th
21	twenty-first	21st
100	one hundredth	100th

Watch the spelling changes: five becomes fifth, eight becomes eighth, nine becomes ninth, twelve becomes twelfth, twenty becomes twentieth.

Ordinals are used for dates (“March 5th” or “the fifth of March”), rankings (“she finished third”), floors (“the twenty-second floor”), and anniversaries (“their fiftieth anniversary”).

Decimal Numbers in Words

For numbers with decimals, say “point” and then read each digit after the decimal individually:

3.14 = “three point one four”
0.5 = “zero point five” (or “point five” in casual speech)
2.718 = “two point seven one eight”

For money, use “and” instead of “point” and read the cents as a whole number:

$4.99 = “four dollars and ninety-nine cents”
$0.75 = “seventy-five cents”

Skip the Manual Work

Our Number to Words Converter spells out any number instantly, formatted correctly for checks, legal documents, or general use. Enter the number and get the word form with proper hyphenation and capitalization.

Frequently Asked Questions

Should I write “zero” or “0” in formal writing?

In most style guides, spell out “zero” when it appears in running text (“The account balance dropped to zero”). Use the digit 0 in tables, data sets, measurements, and technical writing. In legal contexts, always duplicate: “zero (0) defects.” AP Style treats zero like other small numbers and spells it out.

Do I hyphenate “twenty one” or write “twenty-one”?

Always hyphenate compound numbers from twenty-one through ninety-nine. This applies in all contexts: “She is twenty-one years old,” “page thirty-seven,” “the forty-fifth president.” The hyphen isn’t optional—omitting it is a grammatical error in every major English style guide.

How do I write a check for an even dollar amount?

Write the dollar amount in words, then add “and 00/100” to indicate zero cents. For example, a check for $500 should read: “Five hundred and 00/100.” Draw a line through the remaining space on the amount line to prevent anyone from adding extra words. Some people write “and no/100” or “and xx/100,” which are also acceptable.

What is the difference between “a billion” in the US and the UK?

Today, both countries use the short scale where one billion equals 1,000,000,000 (10^9). The UK officially adopted the short scale in 1974. Before that, the UK used the long scale where one billion meant one million million (10^12). Some older British texts and several European languages (French, German, Spanish) still follow the long scale, so “billion” can be ambiguous in international contexts. When precision matters, state the actual figure.

When should I spell out a number at the start of a sentence?

Always. No major style guide permits starting a sentence with a digit. “350 guests attended the event” should become “Three hundred fifty guests attended the event.” If the number is awkward to spell out (like 1,247,893), restructure the sentence instead: “The event drew 1,247,893 visitors” rather than trying to spell out a seven-digit number at the start.