Numbers to Words Converter — Spell Out Numbers in English and Vietnamese

When do you need to write numbers in words?

• Cheques/checks: The written amount must match the numeric amount
• Legal documents: Contracts often require amounts written in words
• Formal writing: Style guides recommend writing numbers under 10 in words
• Education: Teaching children to read and write numbers
• Vietnamese documents: Official documents require amounts in Vietnamese words

Rules for writing numbers in English

Basic rules

• Numbers 1–9: always write as words (one, two, three...)
• Numbers 10+: can use numerals in informal writing
• Large round numbers: write as "1 million" not "1,000,000" in running text
• Beginning of sentence: always write as word (never start with a numeral)

Cardinal vs Ordinal

• Cardinal: count (one, two, three) — how many
• Ordinal: order (first, second, third) — what position

Currency format

• 99.50 → "ninety-nine dollars and fifty cents"
• 1,000 → "one thousand dollars"

Vietnamese number words

Special Vietnamese rules

Vietnamese has unique rules that differ from direct translation:

• Unit digit 1 after tens becomes mốt (not một): 21 = "hai mươi mốt"
• Unit digit 5 after tens becomes lăm (not năm): 25 = "hai mươi lăm"
• Single digit after hundreds uses linh: 101 = "một trăm linh một"

How to convert numbers to words free

1. Go to Numbers to Words
2. Type any number
3. Select format: Cardinal, Ordinal, or Currency
4. Select language: English or Vietnamese
5. Copy the result

Why cheques still spell out amounts

Writing an amount in both digits and words is a tamper-control measure, and it is the reason this conversion still matters in banking, contracts, and invoices.

A digit is easy to alter — 100 becomes 1000 with a single stroke. Words are not: turning "one hundred" into "one thousand" requires rewriting the phrase visibly. When the two disagree, most jurisdictions and banking rules treat the written words as authoritative.

This is why the words on a cheque are underlined or followed by a line of dashes to the edge of the field: it prevents anything being added afterwards.

Short scale and long scale

"A billion" does not mean the same thing everywhere, and financial documents have gone wrong over it.

Under the long scale still used in France, Germany, Spain, and much of Latin America, a billion is a million million — a thousand times larger than the short-scale billion. The UK officially moved to the short scale in 1974, but older British texts use the long scale.

For international documents, write the digits alongside the words, or use scientific notation, rather than relying on a term whose meaning depends on the reader's country.

The "and" question

British and American conventions differ:

• British English: "one hundred and twenty-three"
• American English: "one hundred twenty-three"

Both are correct in their own register. In formal financial writing, "and" is conventionally reserved to mark the decimal point — "one hundred twenty-three and 45/100 dollars" — which is why American cheque convention omits it from the whole-number part.

Hyphenation

Compound numbers from twenty-one to ninety-nine take a hyphen: twenty-one, forty-seven, ninety-nine. Hundreds, thousands, and millions do not: two hundred, three thousand.

So 5,342 is "five thousand three hundred forty-two" — one hyphen, in forty-two only. This is the most frequently botched rule in formal writing.

Vietnamese specifics

Vietnamese number words have rules with no English equivalent, which is why naive conversion produces text that reads as obviously wrong:

• mốt instead of một for a final 1 after twenty: 21 is hai mươi mốt, not hai mươi một.
• lăm instead of năm for a final 5 after ten: 15 is mười lăm, 25 is hai mươi lăm.
• linh / lẻ fills an empty tens position: 105 is một trăm linh năm.
• tư instead of bốn commonly for a final 4 after twenty: 24 is often hai mươi tư.

These are not optional stylistic variants — using the base form sounds incorrect to a native speaker in the same way "twenty-one" rendered as "two ten one" would in English.

Frequently asked questions

How do I write decimals in words?

For currency, the convention is a fraction over 100: "forty-five and 25/100 dollars". For general use, name the digits: 3.14 is "three point one four", not "three point fourteen".

Should I capitalise the words?

On cheques and formal documents, capitalising only the first word is standard. Some legal drafting capitalises the entire amount for emphasis, which is a house-style choice rather than a rule.

How are very large numbers named?

Short scale continues million, billion, trillion, quadrillion, quintillion. Beyond that the names are rarely used in practice and scientific notation is clearer.

What about zero?

In cheque writing, a zero amount for cents is written as "and 00/100". Standalone zero is written "zero" in American usage and sometimes "nil" in British financial contexts.

Does the conversion happen on a server?

No. It runs entirely in your browser, so amounts from a contract or invoice never leave your device.