Writing Numbers Out in Words

Quick Answer

Type digits and you get numbers in words. Type words and you get digits back.

For example, Input: 4213.75. Output: four thousand two hundred thirteen point seven five. Negatives come back with negative in front, and the decimal part is read one digit at a time.

The number to words converter works out which direction you meant from what you typed. Paste an amount straight out of a spreadsheet and it offers to strip the currency symbol and the commas for you.

Where does the hyphen go?

Between a ten and a unit, and nowhere else.

A compound ten is the only place one belongs. Twenty-one, thirty-four and ninety-nine all take a hyphen. Hundreds, thousands and millions do not, therefore four thousand two hundred thirteen carries none at all. Every major style guide agrees on this, but four-thousand looks tidy enough that people write it anyway.

That is the common mistake this tool quietly fixes. Avoid inserting hyphens by feel and the spelled number will match what a contract, a cheque or a proofreader expects.

How does the conversion work?

The number gets cut into groups of three digits, and each group is spelled with the same small routine.

For example, 4213 splits into 4 and 213. The first group takes the word thousand after it, the second takes nothing. Inside a group, anything under twenty has its own word, the tens are joined to their unit with a hyphen, and a leading digit gets hundred after it.

Reading words back is a running total instead. Each value word gets added, a hundred multiplies what is in hand, and a scale word such as thousand pushes the running total up and resets it. That is why one hundred five and one hundred and five both come back as 105.

One hundred and five, or one hundred five?

Both are correct English. The difference between them is which side of the Atlantic you are on.

American English drops the and. British English keeps it, and a British primary school will mark its absence wrong. The converter writes the American form, because that is what cheque and invoice software expects and what reads without ambiguity in a legal clause.

Going the other way it accepts everything. Commas, hyphens, the word and, and minus in place of negative all parse. So you can paste a phrase copied out of a British contract and get digits back without editing it first.

Why is 4.75 read digit by digit?

Decimals are read aloud one digit at a time here, because reading the decimal part as a whole number breaks down past two places.

Four point seventy-five is clear enough. Four point one two five is not, because one hundred twenty-five thousandths and twelve point five are both plausible readings of the same phrase. Digit by digit stays unambiguous at any length, which is why aviation, finance and dictation all settled on it.

Money is the exception, and it is worth knowing why. A cheque does not write the cents as words at all. Instead it uses a fraction over 100, so 4213.75 becomes four thousand two hundred thirteen and 75/100.

How do I write an amount on a cheque?

Spell out numbers for the whole part, capitalise the first letter, then add the cents as a fraction. Banks want you to write numbers in words for a reason worth knowing.

For example, Input: 4213.75. Output on the line: Four thousand two hundred thirteen and 75/100. Fill the rest of the line with a horizontal stroke so nothing can be added after it.

The reason banks want words at all is that digits can be altered and a sentence cannot. A 1 in front of a figure changes everything, but nobody edits four thousand into fourteen thousand convincingly. When the two lines disagree, the words win.

Short scale vs long scale, and why a billion moved

A billion means a thousand million here. It has not always meant that.

Under the short scale, each new word is a thousand times the last: million, billion, trillion, quadrillion. Under the long scale, each new word is a million times the last, so a billion was a million million. British English used the long scale until the 1970s, and French, German and Spanish still do.

Unlike a rounding difference, this one is a factor of a thousand. Instead of assuming, check any translated financial figure against its digits. This converter uses the short scale throughout and stops at 999,999,999,999,999, which is the largest value a browser can hold as an exact whole number.

If you want the same figure as a numeral, the Roman numeral converter handles that, and the binary converter handles base two. Nothing you type here is uploaded.