How numbers work in English

English numbers are easy to build and easy to mishear. The system is simple: learn about twenty words and you can say any number up to a billion. The hard parts are a few spellings, the sound of thirteen against thirty, and some small rules about and, s and commas. This page covers all of them.

Zero to twelve: learn these as words

The first thirteen numbers have no pattern. Learn them as words, the way you learn cat or house:

Three sounds to watch:

• three starts with th (tongue between the teeth). Without it, three sounds like tree.
• five and seven have a real v (top teeth on the bottom lip), not a b or a w.
• eight sounds like ate. The gh is silent.

One and two are also odd to read: one sounds like won, and two sounds like too and to.

Thirteen to nineteen: the -teens

From 13 to 19 English adds -teen to the digit. That is why people aged 13 to 19 are called teenagers.

Three of them change the digit: thirteen (not threeteen), fifteen (not fiveteen), and eighteen, which has only one t (not eightteen).

Twenty to ninety: the -ty tens

The tens add -ty:

The same changes come back: thirty, fifty, and eighty with one t. And one more that catches almost everyone: forty has no u. Four and fourteen keep it; forty drops it. Fourty is wrong, and it is one of the most common spelling mistakes in the language. Ninety, on the other hand, keeps the e of nine.

Thirteen or thirty? The stress

These pairs sound close, and in a noisy shop or on the phone they are easy to mix up: 13 and 30, 14 and 40, 15 and 50, all the way to 19 and 90.

The difference is the stress, the strong part of the word:

• -teen numbers are strong at the end: thirTEEN, fifTEEN. The ee is long and you hear a clear n.
• -ty numbers are strong at the front: THIRty, FIFty. The end is short and weak. In American English the t in -ty often sounds like a soft d (thirdy).

Now the bad news. When you count (thirteen, fourteen, fifteen), or when a noun comes straight after the number (thirteen people), the stress on -teen often moves to the front. Then thirteen and thirty sound very close indeed.

Native speakers mishear them too, so they check: Sorry, one three or three oh? Do the same when a price, a time or a room number matters. And when you say a -teen number yourself, give the end its full long ee and its n.

Twenty-one to ninety-nine: tens plus a digit, with a hyphen

Every number from 21 to 99 is a ten plus a digit, in that order:

• 21 = twenty-one
• 45 = forty-five
• 99 = ninety-nine

When you write these numbers in words, put a hyphen (-) between the two parts: twenty-one, not twenty one. Nothing else changes: English has no and inside these numbers, and the digit never changes its form.

A hundred and one: hundred, and the British "and"

For 100, say a hundred or one hundred. A hundred is the normal everyday choice; one hundred sounds more exact, and people use it when they want to be clear. Both are correct. After thousand, though, you must use one: 2,100 is two thousand one hundred, never two thousand a hundred.

Then comes the most British rule in this page. In British English, you put and after hundred when a smaller number follows, and after thousand when what follows is under a hundred:

• 101 = a hundred and one
• 250 = two hundred and fifty
• 3,005 = three thousand and five
• 999 = nine hundred and ninety-nine

In American English, people often leave the and out: two hundred fifty. Both are understood everywhere. Some American teachers say the and is wrong, but it is standard English everywhere else; this page uses the British form.

Hundred, thousand, million: no s after a number

This rule catches almost every learner once. After a number, hundred, thousand and million never take an s:

• two hundred people (not two hundreds)
• five thousand pounds (not five thousands)
• three million years (not three millions)

But when there is no number in front, you add the s and the word of:

• hundreds of people
• thousands of pounds
• millions of years

This means a large number that you are not counting exactly. Two hundred people is a fact; hundreds of people is a lot of people. The same rule works with dozen (twelve): two dozen eggs, but dozens of eggs. The words are also in the Numbers and amounts lesson in chapter 8 of the English course.

Zero: oh, nought, nil or zero?

English has four ways to say 0. Which one depends on where the 0 is:

Zero is never wrong, and Americans use it in most of these places (zero point five). With phone numbers, British speakers also say double for a digit that comes twice: 7755 is double seven double five. And in tennis, 0 is love.