How to Convert Numbers to Words in English

The Basic Number Words (1–19)

These must be memorised individually:

one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen, fifteen, sixteen, seventeen, eighteen, nineteen

Note that eleven and twelve are irregular (not "oneteen" and "twoteen"). Thirteen through nineteen all end in "-teen."

Tens and Compound Numbers (20–99)

The tens are: twenty, thirty, forty, fifty, sixty, seventy, eighty, ninety. Note "forty" not "fourty" — this is one of the most common misspellings in English.

Compound numbers from twenty-one to ninety-nine use a hyphen: twenty-one, thirty-five, forty-two, ninety-nine. Never write "twenty one" without a hyphen.

Hundreds and Thousands

For hundreds, add "hundred" after the digit word: one hundred, two hundred, five hundred. No "and" in American English between the hundreds and tens. In British English, "and" is used: "one hundred and twenty-three" (UK) vs "one hundred twenty-three" (US).

For thousands: one thousand, ten thousand, one hundred thousand. Numbers above a thousand follow the same pattern with "thousand" as a connector: two thousand three hundred forty-five.

Millions, Billions, and Trillions

The scale words are: million (10⁶), billion (10⁹), trillion (10¹²), quadrillion (10¹⁵), quintillion (10¹⁸).

For specific numbers: 1,500,000 = one million five hundred thousand. 2,750,000,000 = two billion seven hundred fifty million. 3,400,000,000,000 = three trillion four hundred billion.

Important: The British "billion" traditionally meant 10¹² (a million million), while the American "billion" means 10⁹ (a thousand million). In modern usage, the American definition is standard internationally, but in formal British legal documents the potential ambiguity is sometimes flagged.

When to Write Numbers as Words (Style Guide Rules)

Different style guides have different rules. The most common conventions:

• AP Style (journalism): Spell out one through nine; use digits for 10 and above.
• Chicago Style (books): Spell out one through one hundred; use digits above.
• MLA Style (academic): Spell out numbers that can be written in one or two words; use digits for the rest.
• Always spell out: Any number that starts a sentence. Rewrite the sentence if the number is large: instead of "42,000 respondents were surveyed" write "The survey had 42,000 respondents."
• Always use digits for: Exact measurements (5 km, 3.5 kg), percentages (17%), ages (she is 32), addresses (10 Downing Street), years (2026), pages and chapters (Chapter 12), time with AM/PM (3:30 PM).

Writing Numbers on Cheques

Cheques require the full amount in words to prevent fraud. The convention is:

Format: [Dollar amount in words] and [cents]/100

Example: $1,247.89 → "One thousand two hundred forty-seven and 89/100 dollars"

For round amounts: $500.00 → "Five hundred and 00/100 dollars"

Use our Number to Words converter for any number. It handles integers, decimals, and produces correct hyphenation automatically.

Frequently Asked Questions

When should you spell out numbers in writing?

Most style guides (AP, Chicago, MLA) recommend spelling out numbers one through nine or one through ten, and using numerals for 10 or higher. Always spell out numbers at the start of a sentence. Use numerals for exact measurements, percentages, ages, and statistics in most contexts.

How do you write large numbers like one million in words?

Write: one million (1,000,000), one billion (1,000,000,000), one trillion (1,000,000,000,000). For specific numbers: 1,250,000 = one million two hundred fifty thousand. Note that in the UK, a billion traditionally meant one million million, but the American definition (one thousand million) is now standard globally.

Should you use a hyphen in compound numbers?

Yes. Compound numbers from twenty-one to ninety-nine are hyphenated when written as words: twenty-one, forty-five, ninety-nine. Hyphenate compound adjectives: a twenty-five-year-old man. Numbers in the hundreds and thousands do not take hyphens in the thousands/hundreds portion: three hundred forty-five.

How do you write check amounts in words?

Write the full dollar amount first, then "and", then the cents as a fraction: "One hundred twenty-five and 50/100 dollars." For amounts under a dollar: "Zero and 75/100 dollars." Always write the cents as a fraction (not as words) on checks to prevent fraud.