What is the largest number this tool can convert?

Up to 999 trillion (999,999,999,999,999) in English and up to 999조 9999억 9999만 9999 in Korean. This covers virtually all practical cheque, invoice, and legal document amounts.

How does the currency / cheque mode work?

For English output with USD, the integer part is spelled out followed by "dollars and XX/100" — the standard US cheque format where decimals become cents, rounded to the nearest cent (1.999 becomes two dollars and 00/100). For Korean output with KRW, the integer part is spelled in Korean followed by 원 (since 전 is not used in modern Korean banking) and decimals are dropped. Tick the contract format to get the contract-style wording instead.

Does any data leave my device or get stored on a server?

No. All conversion logic runs entirely in your browser using JavaScript. Your numbers are never uploaded, logged, or shared with any server. The last input is saved locally in your browser storage only to restore your session.

Why does Korean omit 일 before 천, 백, and 십?

This is a standard Korean convention: when the leading digit of a unit position (thousands, hundreds, tens) is exactly one, the digit 일 is implied and not spoken. So 1,000 is 천 (not 일천), 100 is 백 (not 일백), and 10 is 십 (not 일십). For digit values 2–9, the digit is always spoken (이천, 삼백, 사십, etc.). The contract format switches this off and writes 일천, 일백, 일십 as Korean contracts often do.

Can I convert negative numbers or numbers with decimals?

Yes. Prefix any number with a minus sign ( - ) for negative; -0 is treated as plain zero. In cardinal mode, decimal digits are read out individually after "point" (English) or 점 (Korean). In currency mode, decimals become cents for USD (rounded to the nearest cent, XX/100) and are dropped for KRW since jeon is not used in modern Korean practice.

What does the Korean contract format option do?

It appears when the output language is Korean and the mode is Currency / Cheque. Off, the result looks like 백이십오만 원. On, it is written the way amounts appear in Korean contracts and promissory notes: 일 is kept before 천, 백 and 십 (일천, 일백, 일십), there is no space before 원, and the amount starts with 일금 and ends with 정, as in 일금 일백이십오만원정. This is a common convention, not a legal requirement, so check the form your contract or counterparty expects.

🔢 Number to Words Converter — English & Korean, Cardinal & Currency

Type any number and instantly get it spelled out in English or Korean words — choose between plain cardinal form (one thousand two hundred thirty-four) and currency/cheque style (one thousand two hundred thirty-four dollars and 00/100). For Korean amounts there is also an optional contract format that writes 일금 일천이백삼십사원정, the way amounts are written in Korean contracts and promissory notes. Supports decimals and numbers all the way up to trillions. Everything runs in your browser with zero upload and no account needed.

Number

Output Language

Mode

Private by design. This tool runs entirely in your browser — nothing you enter is uploaded, and it works offline.

About

This tool implements number-to-words spelling logic entirely in client-side JavaScript — no libraries, no server round-trips. For English, it breaks numbers into groups of three digits (hundreds, thousands, millions, billions, trillions) and names each group using standard US conventions, joining with hyphens for compound tens (twenty-one). For Korean, it uses groups of four digits with the traditional units 만 (10,000), 억 (100,000,000), and 조 (1,000,000,000,000), and by default follows the rule of omitting 일 before 천/백/십. Currency mode formats results for cheque writing: USD gives "dollars and XX/100" with the decimals rounded to the nearest cent; KRW gives the Korean spelled amount followed by 원. For Korean currency output, an optional contract format keeps 일 before 천/백/십 (일천, 일백, 일십), removes the space before 원 and wraps the amount as 일금 … 원정, so 1,250,000 reads 일금 일백이십오만원정. Decimal digits in cardinal mode are read out individually after "point" or 점.

How to use

Enter any integer or decimal number in the input field. Thousands separators (commas) are accepted.
Choose the output language — English for English words, 한국어 for Korean (한글) words.
Select a mode: Cardinal for plain number words, or Currency / Cheque for check-writing format.
For Korean currency output, optionally tick 'Contract format (일금 ○○원정)' to get the wording used in contracts and promissory notes.
Click Convert to Words (or press Enter) to generate the result.
Click Copy to copy the result to your clipboard, ready to paste into a cheque, invoice, or document. For a Korean contract, turn on the contract format first.

FAQ

What is the largest number this tool can convert?: Up to 999 trillion (999,999,999,999,999) in English and up to 999조 9999억 9999만 9999 in Korean. This covers virtually all practical cheque, invoice, and legal document amounts.
How does the currency / cheque mode work?: For English output with USD, the integer part is spelled out followed by "dollars and XX/100" — the standard US cheque format where decimals become cents, rounded to the nearest cent (1.999 becomes two dollars and 00/100). For Korean output with KRW, the integer part is spelled in Korean followed by 원 (since 전 is not used in modern Korean banking) and decimals are dropped. Tick the contract format to get the contract-style wording instead.
Does any data leave my device or get stored on a server?: No. All conversion logic runs entirely in your browser using JavaScript. Your numbers are never uploaded, logged, or shared with any server. The last input is saved locally in your browser storage only to restore your session.
Why does Korean omit 일 before 천, 백, and 십?: This is a standard Korean convention: when the leading digit of a unit position (thousands, hundreds, tens) is exactly one, the digit 일 is implied and not spoken. So 1,000 is 천 (not 일천), 100 is 백 (not 일백), and 10 is 십 (not 일십). For digit values 2–9, the digit is always spoken (이천, 삼백, 사십, etc.). The contract format switches this off and writes 일천, 일백, 일십 as Korean contracts often do.
Can I convert negative numbers or numbers with decimals?: Yes. Prefix any number with a minus sign ( - ) for negative; -0 is treated as plain zero. In cardinal mode, decimal digits are read out individually after "point" (English) or 점 (Korean). In currency mode, decimals become cents for USD (rounded to the nearest cent, XX/100) and are dropped for KRW since jeon is not used in modern Korean practice.
What does the Korean contract format option do?: It appears when the output language is Korean and the mode is Currency / Cheque. Off, the result looks like 백이십오만 원. On, it is written the way amounts appear in Korean contracts and promissory notes: 일 is kept before 천, 백 and 십 (일천, 일백, 일십), there is no space before 원, and the amount starts with 일금 and ends with 정, as in 일금 일백이십오만원정. This is a common convention, not a legal requirement, so check the form your contract or counterparty expects.

Ran 31 times in the last 29 days. Measured on our own servers, 2026-09-06–2026-10-05.