How do letters map to numbers on a phone?

2 is ABC, 3 is DEF, 4 is GHI, 5 is JKL, 6 is MNO, 7 is PQRS, 8 is TUV and 9 is WXYZ. Keys 1 and 0 have no letters.

Why do 7 and 9 have four letters?

Because 26 letters do not divide evenly across eight keys. Three each covers 24, so two keys take an extra one, and PQRS and WXYZ were chosen.

Can I convert a number back into a word?

Not to a single word. Each digit represents three or four letters, so a seven-digit number has thousands of possible combinations — the conversion only works reliably in one direction.

Do vanity numbers still work on modern phones?

Yes. Smartphone diallers accept letters and convert them automatically, and the letters remain printed on the keypad for exactly this reason.

How long can a phone word be?

Seven letters for a North American local number, matching the digits after the area code. Toll-free vanity numbers work the same way after the 800-style prefix.

Are vanity numbers actually more memorable?

Considerably. A word is a single chunk to remember where seven digits are seven, which is why the format has survived decades of advertising.

Predictive text for numeric keypads. Because 4663 could be GOOD, HOME, HOOD or HONE, it guessed the most likely word — the same ambiguity this page describes, put to work.

Why do 1 and 0 have no letters?

They were reserved for signalling and operator functions in the original telephone system, so no letters were ever assigned to them.

Phone Number Converter

Convert phone digits to possible letters.

About the Phone Number Converter

Convert a phone number into the letters on a keypad, or a word back into digits — the trick behind numbers like 1-800-FLOWERS.

How to use it

Enter a number to see letter combinations.
Or enter a word to get the digits.

The formula

Every letter maps to the digit it shares a key with on a standard telephone keypad. The mapping has been fixed since the 1960s.

2 = ABC · 3 = DEF · 4 = GHI · 5 = JKL
6 = MNO · 7 = PQRS · 8 = TUV · 9 = WXYZ

Keys 1 and 0 carry no letters, which is why vanity numbers never contain them. Note that 7 and 9 carry four letters each while every other key carries three — the alphabet has 26 letters and only eight keys to spread them across.

The conversion loses information in one direction only. A word gives exactly one number, but a number maps back to thousands of possible letter combinations, which is what made predictive text on old handsets possible — and occasionally infuriating.

Worked examples

Word	Digits	Well-known number
FLOWERS	356-9377	1-800-FLOWERS
HOLIDAY	465-4329	travel bookings
CONTACT	266-8228	generic business line
LAWYERS	529-9377	legal advertising

Notice that FLOWERS and LAWYERS both end in 9377. Different words, same digits — because S, R and W do not all sit on separate keys. This collision is exactly why a phone number cannot be reversed into a single word, and why a good vanity number has to be checked in the direction that matters: does the word give the number you actually own?

Common mistakes

Using letters that do not exist on the keypad. Keys 1 and 0 carry no letters, so no word can map to them. Any vanity number containing a 1 or 0 has to work around it.
Assuming the mapping is universal. It is standard across North America and most modern handsets, but some older European keypads used different arrangements, and a few had no letters at all.
Forgetting the number must fit. A North American local number has seven digits, so the word must be seven letters — or the phrase must total seven. Longer words simply do not fit.
Expecting a number to reverse into one word. It cannot. Each digit stands for three or four letters, so a seven-digit number has thousands of possible letter combinations, almost all of them nonsense.

Terms explained

Vanity number: A phone number chosen because its digits spell a memorable word.
Keypad mapping: The standard assignment of letters to digits 2 through 9.
Toll-free prefix: 800, 833, 844, 855, 866, 877 and 888 in North America. Where most vanity numbers live.
T9: Predictive text on numeric keypads, which guessed words from digit sequences. Built on exactly this ambiguity.
Alphanumeric dialling: Entering a number by its letters. Modern phones convert automatically when you type letters into the dialler.
Mnemonic: A memory aid. The entire commercial value of a vanity number is that a word is easier to recall than seven digits.

Common questions

How do letters map to numbers on a phone?: 2 is ABC, 3 is DEF, 4 is GHI, 5 is JKL, 6 is MNO, 7 is PQRS, 8 is TUV and 9 is WXYZ. Keys 1 and 0 have no letters.
Why do 7 and 9 have four letters?: Because 26 letters do not divide evenly across eight keys. Three each covers 24, so two keys take an extra one, and PQRS and WXYZ were chosen.
Can I convert a number back into a word?: Not to a single word. Each digit represents three or four letters, so a seven-digit number has thousands of possible combinations — the conversion only works reliably in one direction.
Do vanity numbers still work on modern phones?: Yes. Smartphone diallers accept letters and convert them automatically, and the letters remain printed on the keypad for exactly this reason.
How long can a phone word be?: Seven letters for a North American local number, matching the digits after the area code. Toll-free vanity numbers work the same way after the 800-style prefix.
Are vanity numbers actually more memorable?: Considerably. A word is a single chunk to remember where seven digits are seven, which is why the format has survived decades of advertising.
What was T9?: Predictive text for numeric keypads. Because 4663 could be GOOD, HOME, HOOD or HONE, it guessed the most likely word — the same ambiguity this page describes, put to work.
Why do 1 and 0 have no letters?: They were reserved for signalling and operator functions in the original telephone system, so no letters were ever assigned to them.

Related calculators

← All 51 calculators