A Canadian work permit Document Number is one letter plus 9 digits, printed in the top-right of the IMM 1442 permit, and changes with every new permit issued
The UCI is your permanent 8- or 10-digit IRCC client ID that stays with you forever across applications, while the Document Number is permit-specific
IRCC uses the Document Number to verify Canadian work experience on Canadian Experience Class and PNP permanent residence applications
If you cannot find your Document Number, sign in to your IRCC online account with GCKey or call the IRCC Client Support Centre
Renewing or extending your work permit issues a new physical permit with a new Document Number; the old number stays on file as evidence of prior status
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As of September 24, 2026. Most Canadian work permits show three different ID numbers and people mix them up constantly: the Document Number (one letter + nine digits, prefix U), the Work Permit Number (one letter + digits, prefix W), and the Unique Client Identifier or UCI (8 or 10 digits). Each serves a different purpose, and putting the wrong one on an IRCC form can hold up your application.
Short answer: A unique alphanumeric identifier (one letter followed by nine digits) printed in the top-right corner of every IRCC-issued work permit. It identifies the specific physical permit, not the applicant, and changes each time a new permit is issued — your UCI stays the same.
The Canada work permit Document Number is a unique alphanumeric identifier printed in the top-right corner of every IRCC-issued work permit. It is one letter followed by nine digits and stays fixed for the lifetime of that specific physical permit. The Document Number identifies the permit itself, not the applicant. Each new permit you receive (after a renewal, extension, or new application) gets a different Document Number, while your underlying IRCC Unique Client Identifier (UCI) stays the same.
The Document Number is what employers, the Canada Border Services Agency, and IRCC officers reference when verifying that you are authorized to work in Canada.
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Where is the document number on a Canadian work permit?
Short answer: In a labelled box in the top-right corner of the physical IMM 1442 permit, on the second page of the permit-and-counterfoil layout. On electronic permits the Document Number appears in the same position on the PDF served through your IRCC online account.
The Document Number sits in a labelled box in the top-right corner of the physical permit, on the second page of the permit-and-counterfoil layout IRCC ships. On electronic permits issued through the IRCC online account, the Document Number appears in the same position on the PDF, usually marked "Document No." or "Document Number". If you have already lost the physical permit, you can pull the Document Number from any IRCC correspondence about the permit, or from your IRCC online account profile.
Three places to find it:
Physical permit: top-right box, page 2 of the permit document.
Digital permit (PDF): same position, labelled "Document No.".
IRCC online account: under "My Documents" or "Application History" once you sign in.
What is the UCI and how is it different from the document number?
Short answer: The Unique Client Identifier (UCI) is the 8- or 10-digit number IRCC assigns the first time you interact with Canadian immigration, and it stays with you forever across every application. The Document Number changes with each new permit; the UCI does not. For every place the UCI appears, including the PR card, see our UCI number guide.
Number
Format
Where to find it
What it identifies
Document Number
One letter and nine digits
Top-right corner of the permit
The specific permit document
Unique Client Identifier (UCI)
Eight digits, sometimes ten
Top of the permit
You, across every IRCC application
Application or file number
Letters and digits
Receipts and IRCC correspondence
One specific application
The Unique Client Identifier (UCI) is the 8- or 10-digit number (written 0000-0000 or 00-0000-0000) IRCC assigns to a person the first time they interact with Canadian immigration. The UCI stays with you forever, across every work permit, study permit, visitor visa, and PR application. The Document Number changes each time you receive a new permit, but the UCI does not.
If a form asks for "UCI" or "client ID," enter the 8- or 10-digit number. If a form asks for "Document Number," enter the letter-plus-nine-digits from your current permit. If a form asks for "Work Permit Number," check the form instructions: IRCC calls the W-prefix number the application number (usually one letter and 9 digits, for example W993830598). Mixing them up is an easy way to get a form rejected.
Identifier
Format
What it identifies
Changes with renewal?
Document Number
One letter + 9 digits (e.g. U123456789)
The specific physical permit
Yes, new permit, new number
Work Permit Number
W + digits
The work-permit application/issue record
Yes
UCI
8 or 10 digits
You, the person, across all IRCC interactions
No, permanent
File Number
E / W / S / V / T + digits
A specific application submission
Each new application gets a new one
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What is the application file number and when does it change?
Short answer: An IRCC-internal tracking number assigned to each submitted application, distinct from both the UCI and the Document Number. File-number prefixes follow patterns by stream (e.g., E + digits for economic class), and a new file number is assigned with every new submission.
The application file number is assigned every time you submit a new application to IRCC, and it changes with each new submission. It is used internally by IRCC to track that specific application's progress. Unlike your UCI (which is permanent), file numbers are application-specific. File-number prefixes follow these patterns:
Economic class applications: E + digits (example: E099977028)
Work permit applications: W + digits
Study permit applications: S + digits
Visitor record applications: V + digits
Temporary resident permit applications: T + digits
These prefixes are application file numbers, not permit document numbers. A single applicant can have multiple file numbers active at once across different applications. Once the application closes, the file number is archived but the UCI remains.
How do I find my work permit document number online?
Short answer: Sign in to your IRCC online account with GCKey or a sign-in partner, open 'View my submitted applications or profiles', and select your active work permit. The Document Number, UCI, and issue/expiry dates are listed on the document's detail page.
Sign in to your IRCC online account using your GCKey or sign-in partner credentials, then open the "View my submitted applications or profiles" section. Your active work permit document will show the Document Number, UCI, and issue/expiry dates on its detail page. The same data appears on every IRCC letter or email referencing your work permit.
Other places it appears:
Physical and digital permit: top-right corner box.
IRCC online account profile under "My Documents."
IRCC correspondence: any decision letter, approval notice, or instruction email.
Employer records: HR departments often store a copy under your I-9 equivalent file.
What if I can't find my Canadian work permit number?
Short answer: Contact the IRCC Client Support Centre and verify your identity with full name, date of birth, and country of birth. A licensed RCIC or lawyer with your written authorization can also retrieve it. If the permit itself is lost or stolen and still valid, IRCC replaces it through form IMM 5009 for a $30 fee.
If you cannot locate your Document Number, the fastest path is to contact the IRCC Client Support Centre. They can confirm the number after verifying your identity with your full name, date of birth, and country of birth. A licensed Regulated Canadian Immigration Consultant (RCIC) or lawyer can also retrieve it on your behalf with signed authorization. Submitting an Access to Information and Privacy (ATIP) request returns a copy of your entire IRCC file, including all permit numbers ever issued, within the Privacy Act's 30-day deadline, which IRCC can extend by up to 30 more days in most cases. If the permit itself was lost, stolen or destroyed and has not expired, apply for a replacement with form IMM 5009. The fee is $30, IRCC asks for the police report number, and its posted processing time for replacing a valid temporary resident document was 8 weeks on September 22, 2026.
Book a consultation with our licensed RCICs at Go Far Global if you're having trouble accessing your documentation or need clarification on your immigration file.
How does the document number affect your legal status in Canada?
Short answer: The Document Number is the primary identifier IRCC, employers, and CBSA officers use to confirm your authorization to work. Employers can ask to see the permit and check this number, and the conditions printed on that specific permit govern your legal status.
The Document Number is the primary identifier IRCC, employers, and Canada Border Services Agency officers use to confirm you are authorized to work. When your permit is about to expire, IRCC's renewal notifications reference this number. Employers may be asked to verify your authorization independently using the Document Number and the conditions printed on your permit.
If your work permit is approaching expiry, file a renewal or apply for a Bridging Open Work Permit (BOWP) before it expires. IRCC recommends applying at least 30 days before your current permit expires. If IRCC receives your application before the permit expires, you can keep working under the same conditions while you wait (maintained status). If the permit expires first, you lose that protection and have to follow IRCC's rules for an expired permit. Check current IRCC processing times before relying on a renewal landing on time.
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Why does IRCC need your document number for PR applications?
Short answer: IRCC uses the Document Number to verify Canadian work experience claims on permanent residence (PR) applications, especially the Canadian Experience Class and Provincial Nominee Program streams. An officer cross-checks the number against your permit history, so it must match your records exactly. A missing or wrong Document Number can hold up the application.
IRCC uses your work permit Document Number to verify Canadian work experience on permanent residence applications, especially through programs like Canadian Experience Class (CEC) and Provincial Nominee Program (PNP). When you claim Canadian work experience on your Express Entry profile, IRCC cross-references your Document Number against the issued permit, the National Occupational Classification (NOC) code on the permit, and the hours you have logged. A mismatched or old Document Number can lead to questions from the officer and slow the file down.
When completing IRCC forms, double-check that you're entering the correct identifier. If the form asks for "document number," enter the U-series number (one letter, nine digits, top-right corner of your permit). If it asks for "work permit number," check the form instructions, because IRCC calls the W-series number the application number. If it asks for "UCI" or "unique identifier," enter the 8- or 10-digit number.
Use our CRS calculator to see how your Canadian work experience affects your Comprehensive Ranking System (CRS) score.
What are the most common mistakes with work permit numbers?
Short answer: Confusing the UCI (8 or 10 digits) with the Document Number (one letter plus 9 digits), using an old permit's number after a renewal, omitting the letter prefix, and transposing digits when entering it on application forms. Any of them can get a form rejected or an application held up.
The most common errors are confusing the UCI with the Document Number, using an old permit's number after a renewal, and omitting the letter prefix. Any of these mistakes can hold up a permanent residence application. The four mistakes to avoid:
Confusing UCI with Document Number. UCI is 8 or 10 digits. Document Number is one letter plus 9 digits. They are not interchangeable.
Using an old permit number. Renewals produce a new Document Number. Always copy from your current permit.
Mixing up application file numbers with permit Document Numbers. File numbers change with each application; Document Numbers belong to a specific physical permit.
Incomplete numbers. Always include the letter prefix when providing your Document Number, U123456789 not 123456789.
What happens to your document number when you renew your work permit?
Short answer: Every renewal or extension produces a new physical permit with a new Document Number. Your UCI stays the same. Keep every previous Document Number on file because PR applications require you to list every period of authorized employment along with its supporting permit identifier.
When you renew your work permit, IRCC issues a new physical permit with a new Document Number. Your UCI stays the same. Keep records of every previous Document Number for PR applications, because Canadian Experience Class requires you to list every period of authorized employment along with the supporting permit identifiers. The chronology of permits is what proves continuous Canadian work experience.
Do family members share the same work permit number?
Short answer: No. Each work permit issued to a family member carries its own unique Document Number, even when the family applied together. Spouses and dependants on open work permits or study permits each receive their own permits with their own identifiers.
No. Each work permit issued to a family member has its own unique Document Number, even if the family applied together. Spouses and dependent children who hold open work permits or study permits receive their own permits with their own identifiers. The only thing shared across a family file is the principal applicant's IRCC file number for the original application, every issued permit has a distinct Document Number and a distinct UCI per person.
For questions about family immigration and work authorization for dependents, our team can help you understand the requirements.
Frequently asked questions
Is the UCI the same as the work permit number?
No. The UCI is your permanent 8- or 10-digit IRCC client ID and stays the same across every application. The work permit number (Document Number, with a letter prefix and 9 digits) is specific to one issued permit and changes when you renew.
Does my document number change when I extend my work permit?
Yes. Every renewal or extension produces a new physical permit with a new Document Number. Your UCI does not change.
Where can I find my UCI if I never had a physical permit?
Sign in to your IRCC online account. Your UCI appears at the top of your profile. If you have never created an account, your UCI also appears on the first decision letter or acknowledgement of receipt IRCC sent you.
What do I do if my employer asks for my work permit number?
Provide the Document Number from the top-right corner of your physical permit (letter prefix + 9 digits). This is what employers use to verify work authorization. Do not give them just your UCI; that is a personal identifier, not a permit verification.
Can I use my old work permit number on a PR application?
Only when listing prior employment periods in your work-experience history. For your CURRENT authorization, you must use the Document Number from your most recent permit. Listing an expired permit as your current authorization can raise questions about your status.
What is the difference between the W prefix and the U prefix?
The W prefix is most commonly seen on work-permit application file numbers; the U prefix is most common on the Document Number printed on the physical permit. The exact prefix depends on the issue era and permit type. Check the label on your specific permit; whichever letter is printed is the correct one to use.
Updated September 24, 2026 by Rami Mamar, RCIC-IRB (License #R515110). Reviewed against IRCC's published guidance on work permit identifiers and the Immigration and Refugee Protection Regulations. For case-specific advice, book a consultation.
Disclaimer
This article is for informational purposes only and does not constitute immigration or legal advice. Immigration laws and policies change frequently. Each case is unique and outcomes depend on individual circumstances. Consult a Regulated Canadian Immigration Consultant (RCIC) before making immigration decisions.
Rami Mamar is an RCIC-IRB licensed immigration consultant and Commissioner of Oaths with over a decade of experience helping clients from Iran, UAE, Syria, Armenia, and worldwide immigrate to Canada. He has overseen 10,000+ immigration cases including Express Entry, work permits, study permits, and family sponsorship applications.
