How do you convert number words to digits?
Read the words left to right, building up each group of three digits until you hit a scale word like thousand or million, then multiply that group by the scale and add it to the running total. "Two million three hundred forty thousand five" becomes 2,340,005. This converter does that for English number words, returning plain digits with no separators.
Using the converter
- Type or paste the number in words, for example
ninety-nine thousand, nine hundred. - Click Convert.
- Copy the digits:
99900.
The input is forgiving about formatting. Upper or lower case, hyphens or spaces, commas, and "and" all work:
| Input | Output |
|---|---|
| one hundred twenty three | 123 |
| One Hundred and Twenty-Three | 123 |
| twelve hundred | 1200 |
| nineteen hundred eighty-four | 1984 |
| seven million and three | 7000003 |
| minus forty two | -42 |
| negative seven | -7 |
| a thousand | 1000 |
How the parser reads a number
The converter reads the words as a sequence of groups, each worth 1 to 999, and each followed by a scale word or by the end of the input. Taking two million three hundred forty thousand five:
- "two" is a group of 2, and "million" scales it: 2,000,000.
- "three hundred forty" is a group of 340, and "thousand" scales it: 340,000.
- "five" is the last group, with no scale: 5.
- The total is 2,340,005.
Within a group, a hundreds part (three hundred, optionally followed by "and") comes first, then the tens and units: a tens word can be followed by one unit word (forty two), and a teen word stands on its own. Scale words have to go from largest to smallest, each used once.
There is one informal exception: when the whole number is a single group, the hundreds part may be 10 to 99 hundred, so "twelve hundred" (1200) and "nineteen hundred eighty-four" (1984) work. That form can't be mixed with thousand or bigger.
Vocabulary
| Kind | Words |
|---|---|
| Units and teens | zero, one, two … nineteen |
| Tens | twenty, thirty, forty, fifty, sixty, seventy, eighty, ninety |
| Multiplier | hundred |
| Scales | thousand, million, billion, trillion |
| Article (first word only) | a, as in a hundred or a thousand |
| Sign (first word only) | negative, minus |
| Connector | and, after hundred or a scale word |
| Ignored | hyphens, commas |
Scale words follow the short scale used in modern English, so billion means 10^9.
Words it rejects
Anything outside that vocabulary stops the conversion with "Unrecognized word:" and the offending word, which makes typos easy to find:
| Input | Error points at |
|---|---|
| fourty | "fourty" (the spelling is forty) |
| one point five | "point" (no decimals) |
| first, second | "first" (no ordinals) |
| one dozen, half | "dozen", "half" |
| 3 thousand | "3" (no digits mixed in) |
| one quadrillion | "quadrillion" |
Words in the wrong order
Knowing every word isn't enough: the words also have to form a proper number. Sequences that don't are rejected with an error that points at the first word out of place, instead of returning a number you didn't mean:
| Input | Error |
|---|---|
| nineteen eighty four | "eighty" can't follow "nineteen"; spoken year style isn't a number |
| one two three | "two" can't follow "one"; digits read one by one aren't a number |
| twenty thirty | "thirty" can't follow "twenty" |
| hundred | Put a number before "hundred" |
| one thousand trillion | "trillion" can't come after "thousand"; scales go largest to smallest |
| negative | Add a number after "negative" |
| one hundred and | The number can't end with "and" |
| one zero | "zero" can only be used on its own |
If you're converting text that might contain phone numbers, years or digit-by-digit readings, those are exactly the cases that will error, so rewrite them in full (one thousand nine hundred eighty-four). To see the standard wording for a figure, paste the digits into number to words; everything it produces converts back here exactly.
Where this is useful
Typical jobs are pulling amounts out of contracts or cheques that state figures in words, cleaning up transcribed speech, and checking the written-out amount on an invoice against the figure. For spreadsheets and scripts, converting to plain digits first makes the values easy to sort and total, for example with the percentage calculator or the basic calculator.
If you're writing your own parser, the group-and-scale approach above is short enough to implement in a few dozen lines; the JavaScript cheat sheet covers the string methods you'd need for splitting and cleaning the input.
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