A-number vs. USCIS number vs. receipt number
People filling in a form are usually looking at several numbers at once and cannot tell which the form wants. Two of them are the same thing under different names; the others are not.
Checked against USCIS guidance on September 25, 2026. The sources are listed at the end of this page.
6 steps · Checklist
Work out which number a form wants
The full list is at the end of the article.
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The short answer
| Number | What it identifies | Looks like |
|---|---|---|
| A-Number | You | "A" followed by seven, eight or nine digits |
| USCIS Number | You — the same digits, no "A" | Nine digits |
| Receipt number | One filing you sent | Three letters followed by numbers |
| DOS Case ID | Your consular case at the State Department | Three letters followed by nine or ten numbers |
A-number and USCIS number are the same number
USCIS defines the USCIS Number as "a unique, 9-digit number assigned to an alien by the Department of Homeland Security that is listed on the front of Permanent Resident Cards (Form I-551 or Green Card) issued after May 10, 2010".
It is your A-number with the "A" dropped. If a form asks for a USCIS number and your card shows nine digits, those digits are the answer.
The receipt number is not your A-number
A receipt number identifies one application. File three forms and you get three receipt numbers, while your A-number stays the same throughout.
It is the number you use to check a case status. How the letters and digits are built is covered in how USCIS case-tracker numbers are structured.
The DOS Case ID is a State Department number
If you went through a consulate, your paperwork also carries a DOS Case ID. USCIS says it is three letters followed by nine or ten numbers, with a different pattern for Diversity Visa immigrants: four numbers, two letters, then five more numbers.
USCIS also notes that on the visa stamp the DOS Case ID is labelled IV Case Number, and that when you enter it you should not include the last two numbers.
The number printed on the card itself
A green card also carries a card number, which identifies that piece of plastic rather than you. Replace a lost card and the card number changes; your A-number does not.
USCIS does not publish a format for it, so treat any site that describes one as unverified. If a form asks for your A-number or USCIS number, it is not asking for this.
6 steps · Checklist
Work out which number a form wants
Match the number in front of you to what the form is asking for.
Check what the field is called
A-Number and USCIS Number ask for the same digits.
Rule out the receipt number
Three letters then numbers means it identifies a filing, not you.
Rule out the DOS Case ID
A State Department number from your consular case.
Rule out the card number
It identifies the plastic and changes when the card is replaced.
Pad to nine digits if the field needs nine
Insert a zero after the "A".
Use the same number on every form in one filing
Mismatched numbers across a package cause avoidable delay.
Free, and yours to edit — tick items off on the web or in the MyCheck app.
Frequently asked questions
Is my USCIS number the same as my A-Number?
Yes. USCIS defines the USCIS Number as a unique 9-digit number listed on the front of green cards issued after May 10, 2010. It is the A-Number without the "A" prefix.
Is my receipt number my A-Number?
No. A receipt number identifies a single application and starts with three letters. Your A-Number identifies you, starts with "A", and does not change between filings.
What is the DOS Case ID?
A State Department number for your consular case: three letters followed by nine or ten numbers, or for Diversity Visa immigrants four numbers, two letters and five more numbers. On a visa stamp it is labelled IV Case Number.
Is the number on the front of my green card my A-Number?
The 9-digit USCIS Number is. The separate card number identifies that physical card and changes when the card is replaced.
More A-Number guides
Sources
MyCheck is not a law firm and this is not legal advice. Every rule on this page is linked to its USCIS source; check the source for your own situation.
