How to Find a WW2 Service Number (Army, RAF and Navy)

To find a WW2 service number, check the papers at home first: pay book, release papers, letters, medal boxes and the backs of photographs. If he died in service, his CWGC record shows it. Online, the daily casualty lists (WO 417), the 1939 Absent Voter Lists and the C.S. 20 medal cards all record service numbers. Most of these charge.

Key facts

Why it matters: The National Archives advises searching with the service number alone if you have it
Check first: Pay books, release papers, letters, medal boxes and photographs at home
If he died: CWGC records can be searched by service number and usually show it
Online: Casualty lists (WO 417), 1939 Absent Voter Lists, C.S. 20 medal cards (charges apply)
No number?: You can still apply; full name and date of birth are required

Based on The National Archives' Army and RAF guides, GOV.UK and CWGC, checked 31 October 2026.

No luck? Apply for the service record anyway. The number helps, but it is not required.

Why the service number matters

Names repeat. Many men shared a name, and some shared a birth year too. The number pins down the right man.

The National Archives’ own advice for its catalogue is blunt: if you have a service number, try searching with that alone.

1. Look at home first

Most families already hold it, without knowing. Check:

His pay book or release papers. Official documents carried his number.
Letters he wrote, or received. Envelopes and letterheads may carry his number, rank and unit.
Medal boxes and slips. GOV.UK says WW2 campaign medals were issued unnamed, so the medals will not help. Any box, slip or letter they came with might.
Photographs. Look on the back. Studio and group photos are sometimes annotated.
Other papers. Discharge certificates, union or employer letters, and pension papers are all worth a look.

Ask older relatives to look too. Papers end up in wallets, bibles and drawers.

2. Did he die in service? Search CWGC

The CWGC find war dead search is free. CWGC says you can search by name, service number, regiment and country. Records show the number where it is known.

Not there? CWGC suggests entering just the surname, initials and war, then refining. See our guide to finding a WW2 grave.

3. Was he wounded, missing or captured? Search the casualty lists

The daily British Army casualty lists (WO 417) are on Findmypast (charges apply). The National Archives says they cover officers, other ranks and nurses, and state rank, service number, date and type of casualty. Sometimes they give the battalion too.

Captured? POW lists and liberation questionnaires also carry numbers. See how to trace a WW2 prisoner of war.

4. Search the 1939 Absent Voter Lists

Servicemen away from home could vote by proxy or post. The National Archives says the Absent Voter Lists record the address, service number and regimental details of each person.

The 1939 lists, taken from electoral registers at the British Library, are searchable by name on Ancestry and Findmypast (charges apply). Search with his home address in mind.

5. Search the WW2 Army medal cards (C.S. 20)

After the war, soldiers could claim their campaign medals on application cards known as C.S. 20. The National Archives says about 1.7 million cards survive, for soldiers of the British Army and other units run by the War Office. They are searchable on Forces War Records (charges apply).

6. Did he die in service? Search the soldiers’ effects ledgers

The soldiers’ effects ledgers, April 1901 to March 1960, list money owed to soldiers who died in service. They come from the National Army Museum and are on Ancestry, searchable by name or regiment (charges apply).

7. RAF: use the catalogue and the registered number

RAF records transferred from the MOD are going into AIR 85 (airmen) and AIR 84 (officers). Search by surname and year of birth; you do not need the number to start.

For officers, many AIR 84 entries show a registered number, such as A123456/40 (an illustration of the format). The National Archives explains the last two digits are the year of commission, and you can use it with the Air Force Lists to find the service number. Full detail in our RAF WW2 service records guide.

8. Royal Navy: ask the MOD

Navy records are still with the MOD. GOV.UK asks for full name and date of birth, plus the number if known. See Royal Navy WW2 service records.

9. Merchant Navy: check the medal records

Merchant seamen were identified by discharge book (‘A’) numbers. The National Archives says the WW2 medal records in BT 395 usually list the discharge book number. See our Merchant Navy WW2 records guide.

10. Gallantry awards and the Gazette

If he won a gallantry award, the London Gazette announcement and the recommendation (WO 373) may carry his number. See WW2 gallantry awards and the London Gazette.

Still no number? Apply anyway

GOV.UK asks for the service number only “if you know it”. The National Archives says place of birth and regiment help narrow the search. Give everything you have:

full name, with every spelling the family uses
date and place of birth
regiment, corps or service, even if uncertain
home address in 1939 to 1945

Then order the record. Our WW2 Army service records guide explains how.

Keep a note of where each number came from

Found a number? Write down the source next to it: “pay book”, “CWGC record”, “envelope, 1943”. If two sources disagree, you will know which to trust. An official document beats a family note. A number on two independent documents is about as safe as it gets.

A warning about family memory

Some men remembered their number for life. Some families remember it wrong. Treat a number from memory as a lead. Confirm it against a document before you rely on it.

FAQ: Finding a WW2 service number

Can I get a WW2 service record without a service number?

Yes. GOV.UK asks for the service number only if you know it. The National Archives says place of birth and regiment help narrow the search when you do not have one.

Where is a soldier's service number written?

On almost every official paper he had: pay book, release or discharge papers, and some medal paperwork. It also appears in casualty lists, Absent Voter Lists and CWGC records.

What is an RAF officer's registered number?

Many RAF officer entries in AIR 84 show a registered number instead of a service number, in the form A123456/40. The National Archives says the last two digits give the year of commission, which you can use with the Air Force Lists to find the service number.

Does a WW2 medal show the service number?

No. GOV.UK says WW2 campaign stars and medals were issued unnamed. The box or slip they came in may carry details, so keep any packaging.

Is a service number on the 1939 Absent Voter Lists?

Yes. The National Archives says Absent Voter Lists record the address, service number and regimental details of each person. The 1939 lists are on Ancestry and Findmypast (charges apply).

Did merchant seamen have service numbers?

They were identified by discharge book ('A') numbers. The National Archives says the WW2 medal records in BT 395 usually list the discharge book number.

Sources

Checked 31 October 2026.

The Wartime Attic team

We run Wartime Attic and The Attic Letters on YouTube, which tells untold human stories from history, starting with the Second World War. We write these guides from the official records, and link every fact to its source. More about us.