Washington Driver License Numbers Decoded
As an auto insurance agent Washington state drivers license / identification card numbers have always been a part of my job. I have used them often enough that I have the pattern that the state uses memorized so that if someone tells me their driver’s license number I can usually tell them their birthday. It can be fun to tell people that you can tell their birthday from their checkbook. They do not realize that the driver’s license number they have printed on the check tells all.
Washington state encodes your last name, first initial, middle initial, and your date of birth into your driver’s license number. A Washington Identification Card uses the same number as the driver’s license for someone who does not or cannot drive. This online program by Alan De Smet will calculate a drivers license number for you if you want a good guess at what someone’s license number would be.
His site also has the best explanation I could find of how the system works:
These license numbers look like the following:
WOO**JT546KA- “John T. Woo” born on May 1st, 1946WALKECR579DU- “Christopher R. Walken” born on March 31st, 1943LLLLLFMYYXmb- Pattern deciphered below
Drivers License Status
You can go online and check the status of a Washinton License or ID Card number. The screen shot on the right shows what information is available online.
LLLLL - Last Name, truncated - The first five characters are the first five letters of the last name. If the name is shorter than five characters, the extra space is padded with asterisks (*).
F - First Initial
M - Middle Initial - If no middle initial the space is padded with an asterisk (*).
YY - Year of birth, encoded - This is 100 minus the the two digit year of birth. So someone born in 1998 will be 2 (100-98), as will someone born in 1898.
X - Checksum - This can be calculated if you like math but first you must have the rest of the license figured out.
m - Month of birth, encoded. Look up your birth month on this table. There are two options. In general the state will use the first column. If another person has generated the same license number as you, they’ll use the second column. This is most often needed for twins. (I have no idea what they do after that.)
| Month | 1st | 2nd | Month | 1st | 2nd | |
|---|---|---|---|---|---|---|
| Jan | B | S | Jul | M | 4 | |
| Feb | C | T | Aug | N | 5 | |
| Mar | D | U | Sep | O | 6 | |
| Apr | J | 1 | Oct | P | 7 | |
| May | K | 2 | Nov | Q | 8 | |
| Jun | L | 3 | Dec | R | 9 |
d - Day of month of birth, encoded - Look up the code for your birth’s day of month.
| Date | Code | Date | Code | Date | Code | Date | Code | |||
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | A | 11 | J | 21 | 1 | 31 | U | |||
| 2 | B | 12 | K | 22 | 2 | |||||
| 3 | C | 13 | L | 23 | 3 | |||||
| 4 | D | 14 | M | 24 | 4 | |||||
| 5 | E | 15 | N | 25 | 5 | |||||
| 6 | F | 16 | W | 26 | 6 | |||||
| 7 | G | 17 | P | 27 | 7 | |||||
| 8 | H | 18 | Q | 28 | 8 | |||||
| 9 | Z | 19 | R | 29 | 9 | |||||
| 10 | S | 20 | 0 | 30 | T |
Now back to the checksum, X.
Once you have figured out the rest of the license number you can alternate adding and subtracting the numeric value of each character. The checksum is the single digit remaining, ignoring negative signs or the fact it might be more than 9. In other words, answers of 6, 16 and -6 will all have a checksum digit of 6. The mathematical way to write this is:
checksum = (L1 - L2 + L3 - L4 + L5 - F + M - Y1 + Y2 - M + D) mod 10;
For letters and the asterisk use the numbers in the table below to calculate the checksum:
| Value | Letter | Letter | Letter | Letter |
|---|---|---|---|---|
| 1 | A | J | ||
| 2 | B | K | S | |
| 3 | C | L | T | |
| 4 | D | M | U | * |
| 5 | E | N | V | |
| 6 | F | O | W | |
| 7 | G | P | X | |
| 8 | H | Q | Y | |
| 9 | I | R | Z |
Use to convert the letters in the license number into numbers, before calculating the checksum (the 8th character in the license number). So, using our Christopher Walken example above, we calculate the checksum this way:
W-A+L-K+E-C+R-5+7-D+U
6-1+3-2+5-3+9-5+7-4+4=19 so we use the 9 as the checksum.
How does one calculte the “Checksum”? Thank you, G. De Nevers
Comment by Genevieve De Nevers — August 9, 2007 @ 12:11 pm
There you go. I have added directions on how to calculate the checksum for the driver’s license.
Comment by YeOleImposter — August 12, 2007 @ 1:58 pm
…twins are born, named John Wayne Smith and James Walker Smith? Wouldn’t they have the same number?
Comment by So what happens if... — December 20, 2007 @ 8:49 pm
They would, except that there is a ’second column’ for the month that is used for these duplicates. I have not found the answer for what happens when the triplet, Justin Wilkins Smith, comes in for his license.
Comment by YeOleImposter — December 21, 2007 @ 11:43 am
I WORK WITH THE ARCOLA POLICE DEPT. and I have to know the difference between a D.L. and an I.D. CARD. From WASHINGTON STATE.
Comment by Malcolm — October 26, 2008 @ 11:00 pm
Are you asking if they look different or if the numbers are different?
ID Cards say: Identification Card
Licenses say: Drivers License
Otherwise they are almost identical, including the number. A person can go from a license to an ID card and back to a license and the number will not change — just the card.
I have added the following link to the post where you can actually check the status of a Washinton License or ID Card number
Comment by YeOleImposter — October 27, 2008 @ 7:12 pm
this is wonderful. i use this at work all the time! thank you!
Comment by michelle — November 18, 2008 @ 2:55 pm
MY BF AND I WERE CHECKING THIS OUT - ITS COOL BUT WE COULDNT GET HIS NUMBER RIGHT. WHAT IF HE IS A JR. AND HAS NO MIDDLE NAME. WE TRIED BOTH WAYS AND STILL IT DIDNT MATCH LIKE MINE. IS THERE A DIFFERENCE SHOULD WE PLACE JR “J” AS THE MIDDLE INITIAL OR THE “*”?
Comment by monica — December 31, 2008 @ 12:39 pm
If he has no middle initial, then the the * would be used in that spot. Jr may be treated as part of his last name.
Comment by YeOleImposter — December 31, 2008 @ 8:42 pm
What do you do if someone has two middle names?
Comment by Oran — March 11, 2010 @ 6:55 pm
Just like a double last name, two middle names do not change the formula, just the first initial of the middle name is used.
So if the middle name is ’sally may’ then just the ’s’ is used.
Comment by YeOleImposter — March 11, 2010 @ 9:21 pm