Your UK driving licence number explained
The long string in field 5 of a GB photocard is not random. It is your surname, your date of birth and your initials, encoded — which is why, once you can read it, an incorrectly typed licence number is usually obvious at a glance.
There are sixteen characters printed on the card. Some systems and forms show eighteen; the last two are dealt with further down.
| Position | What it holds |
|---|---|
| 1–5 | The first five letters of the surname |
| 6 | The decade digit of the year of birth |
| 7–8 | The month of birth, plus 50 for female drivers |
| 9–10 | The day of the month of birth |
| 11 | The year digit of the year of birth |
| 12–13 | First initial, then middle initial |
| 14 | An arbitrary digit, usually 9 |
| 15–16 | Two check characters |
Characters 1–5: the surname
The first five letters of the surname. A surname shorter than five letters is padded on the right with the digit 9, so a driver called Ng begins NG999.
A surname longer than five letters is simply cut off at five. Fotheringham begins FOTHE.
Character 6: the decade of birth
One digit: the decade of the year of birth. Someone born in 1985 has an 8 here. Someone born in 2003 has a 0.
Characters 7–8: the month of birth
The month, with one quirk. For female drivers, 50 is added — so January is 01 for a man and 51 for a woman, March is 03 or 53, and December is 12 or 62.
This is the only place in the number where sex is encoded, and it is why two digits are used for something that would otherwise fit in one.
Characters 9–10: the day of birth
The day of the month, with a leading zero where needed. No adjustment for anything.
Character 11: the year within the decade
The final digit of the year of birth. Taken with character 6, this reconstructs the year: an 8 at position 6 and a 5 at position 11 means 1985.
The date of birth is deliberately split rather than written in one block, which is what makes the number look more random than it is.
Characters 12–13: the initials
First initial, then middle initial. A driver with no middle name has a 9 in position 13, so John Smith with no middle name gives J9, and John Andrew Smith gives JA.
Character 14: an arbitrary digit
Usually 9. It exists so that two people whose name, sex and date of birth would otherwise produce an identical number can be told apart, and it is the one position with no meaning you can read off.
Characters 15–16: the check characters
Two characters generated by the DVLA to verify that the rest of the number is internally consistent. They are what stops a mistyped number silently passing for a real one.
Characters 17–18: the issue number
Not printed on the photocard, but present in some DVLA systems and on some forms, which is why you will occasionally see an eighteen-character number.
These two digits record how many licences have been issued to that person. They increase each time a licence is replaced — a renewal, a change of name, a lost card. If you are comparing a sixteen-character number from a photocard against an eighteen-character one from a system, the first sixteen are the part that should match.
A worked example
An invented driver: John Smith, male, born 12 March 1985, with no middle name.
| Part | Value | Why |
|---|---|---|
| 1–5 | SMITH |
Five letters exactly, so no padding |
| 6 | 8 |
The decade digit of 1985 |
| 7–8 | 03 |
March. Male, so nothing is added |
| 9–10 | 12 |
The twelfth |
| 11 | 5 |
The year digit of 1985 |
| 12–13 | J9 |
J for John; 9 because there is no middle name |
| 14 | 9 |
The usual arbitrary digit |
| 15–16 | AB |
Check characters, shown here as an example only |
Which gives SMITH803125J99AB.
A woman born on the same day would differ in one place: positions 7–8 would read 53 rather than 03.
Why this is worth knowing
Mostly because it makes a wrong number visible without looking anything up.
Where a licence number has been transcribed from a photograph or read out over the phone, the commonest errors are a transposed pair of digits in the date of birth and a mistyped surname. Both show up immediately once you know what the parts mean: the surname should be the driver’s surname, and characters 6 to 11 should reconstruct their date of birth. If they do not, the number is wrong, and you find that out now rather than when a check fails.
It is also a good reason to have drivers enter their own licence number rather than have an administrator type it in from a scan. The driver is reading their own licence, and the number they submit is the one on it.
What you cannot do
Work out somebody’s full licence number from their name and date of birth. Position 14 is usually 9 but is not guaranteed to be, and the check characters are generated by a method the DVLA does not publish. Enough of the number is unpredictable that the exercise does not work, and it is not one to attempt.
This also describes the GB format only. Northern Ireland licences are issued by the DVA and use a different, shorter number, and licences issued outside the UK follow whatever their own country does. If your fleet includes those drivers the number will not decode — and, more to the point, the DVLA cannot check them either.
Having drivers confirm their own licence number is part of how the digital D906 works: the driver checks their own details before signing, so the number on file comes from the licence rather than from a transcription.