If you live in the UK and have a US tax requirement, you may be asked for an Individual Taxpayer Identification Number, or ITIN. Before completing the application, establish why the number is required and which documents support that reason.
Get ITIN application support from KBA
ITIN application support: £299 per applicant for a standard eligible application, excluding VAT where applicable. The agreed package covers review of your stated tax purpose and supporting information, permitted CAA document authentication, Form W-7 preparation, submission and agreed follow-up. We confirm any tax-return work, package inclusions and the total payable in writing before you commit. See the current fees and scope.
Khuram Barvi & Accountants Ltd is listed in the official IRS directory of UK acceptance agents. We check the document route before your appointment. The IRS decides whether to issue an ITIN.
Select “ITIN or EIN application” and briefly explain your tax purpose, country of residence and deadline. KBA will confirm availability, the documents needed and the next step. Please keep passport copies and tax numbers out of the initial enquiry.
Start with eligibility
An ITIN is a US tax-processing number for individuals who need a taxpayer identification number but are not eligible for a Social Security number. Being a UK resident does not, by itself, establish eligibility. The application needs an appropriate US tax purpose. IRS: ITIN overview
For example, an eligible individual may need an ITIN to file a US tax return. Other applicants may qualify under a documented exception. Review the reason with your adviser before selecting the relevant box on Form W-7.
An ITIN does not provide permission to work in the United States or change your immigration status. IRS: Form W-7 instructions
Check whether a tax return must accompany the application
An application normally includes Form W-7, the relevant federal tax return and supporting identification documents. Some cases meet an exception to the tax-return attachment requirement, but the exception must be supported by the specified evidence. It is not enough simply to say that no return is due. IRS: Form W-7 instructions
Keep any correspondence explaining why an ITIN is required and show it to the person reviewing your application. It may help them identify the correct route and any additional documents needed.
What does a Certifying Acceptance Agent do?
A Certifying Acceptance Agent, or CAA, can help complete and review Form W-7, authenticate permitted identification documents and submit the application package. Authenticated documents can generally be returned after the appointment, avoiding the need to send those originals to the IRS.
There are limits: CAAs cannot authenticate foreign military identification cards, and their authority for dependent applicants is limited to passports and birth certificates. Additional documentation may need to be sent to the IRS. Tax-return preparation is also a separate service unless the provider includes it in the agreed scope. IRS: applying through a CAA
Prepare for the appointment
Ask for an application-specific document list. A valid passport can establish both identity and foreign status, although some dependent applicants need additional evidence. A normal photocopy is not the same as a copy certified by the issuing agency. IRS: supporting documents
Before your appointment, gather:
- Your current passport or other documents agreed with the CAA.
- Your current mailing address and relevant foreign-address information.
- The tax return or documents supporting an exception, as applicable.
- Details of any previous ITIN and relevant IRS correspondence.
Check that names and personal details are consistent across the application and supporting records. Tell the CAA if you have travel plans so the handling of your identification documents can be discussed before submission.
US tax already withheld? Separate the ITIN application from the refund review
An ITIN identifies you for US federal tax processing; obtaining one does not establish that tax deducted from your income is refundable. The IRS says a nonresident alien claiming a refund of overwithheld or overpaid tax must file an income tax return. Your US tax-residence status and the appropriate return need checking first. See the IRS nonresident filing guidance.
Use this preparation checklist before commissioning an application or return:
1. Identify the year and payment. Record the US tax year, income type, payer and payment date. Gather the statement showing gross income and tax withheld, such as Form 1042-S, Form 1099 or Form W-2 where applicable. The 2025 Form 1040-NR instructions distinguish withholding reported on different forms. Use the instructions for the year being reviewed; do not treat a net bank receipt as a complete tax record.
2. Explain the filing history. Tell your adviser whether a US return has already been filed, whether you have an SSN or an existing ITIN, and whether the payer has issued a corrected statement. If a return is already filed, ask what needs reviewing before sending another return or a new application.
3. Agree who prepares the return and who handles Form W-7. The IRS normally requires a federal return with a new ITIN application unless a documented exception applies. If another adviser prepares your return, coordinate the final signed return, identification-document route and submission responsibility. The W-7 instructions give a specific application-package route; do not independently send duplicate copies to different IRS addresses.
4. Separate the service scopes. Ask whether the quote covers the ITIN application, tax-return preparation, review of possible treaty treatment and later IRS correspondence. These are different tasks. A CAA’s document-authentication role does not determine the refund due, and the amount withheld is not automatically the amount repayable.
Illustrative example — 2025 US tax year, not client work: a UK-based individual has a Form 1042-S showing income and US tax withheld, but no US taxpayer number. The useful next step is to establish the filing position and ITIN eligibility, and agree who will prepare any required return and application package. The statement alone does not establish a refund amount.
Request an ITIN consultation and mention the income type, tax year, whether a withholding statement is available and whether a return is already prepared. Keep account numbers, tax identifiers and document copies out of the initial form; agree secure sharing separately.
US federal administrative guidance checked 18 October 2026. The return reference above is for the 2025 tax year; other years require their corresponding forms and instructions. This checklist does not assess an individual’s treaty entitlement or calculate a refund.
A five-point brief for your first enquiry
You do not need to send identity documents to explain your situation. Use these five points to help KBA identify what needs checking before an application is prepared:
1. Reason and tax year: explain who has asked for the ITIN, why it is needed and which US tax year is involved. If you are unsure about the reason, say so rather than choosing an exception yourself.
2. New application or existing number: say whether you have applied before or already have an ITIN, without including the number. For an older number, start with our ITIN renewal checks.
3. Return or exception evidence: say whether a US federal return has been prepared, whether another adviser is preparing it, or whether you need the attachment requirement reviewed.
4. Applicant and document situation: say whether the application is for you, a spouse or a dependent, and flag an expired document or a name discrepancy. Keep passport numbers, copies and dates of birth out of the enquiry.
5. Timing and scope: mention relevant deadlines, travel dates and your time zone. Ask what the quoted service includes, particularly return preparation, document handling and responses to IRS requests.
Illustrative first enquiry: “I live in the UK and have been asked to obtain an ITIN for a US federal return for [tax year]. My return is being prepared by another adviser. I have not applied before and would like to discuss the documents, scope and appointment arrangements.” This is an enquiry template, not evidence of eligibility or a suggested answer for Form W-7.
Keep tax identifiers and financial records out of the initial form. Ask KBA how to provide any documents needed for the next stage. If your question is about a company identification number, see our EIN guide for overseas founders rather than assuming an ITIN application is the next step.
Allow time for IRS processing
The IRS currently advises allowing seven weeks for an application-status notice, or nine to eleven weeks during the specified tax-season period or for overseas applications. These are published processing expectations, not a guaranteed completion date. A CAA does not make the IRS’s approval decision. IRS: application processing
Speak to KBA about your application
Khuram Barvi & Accountants Ltd appears in the IRS’s UK acceptance-agent directory at 155 Altmore Avenue, London. Check the official IRS listing.
Review KBA’s ITIN and EIN support and our current fees and scope notes, then request a consultation. Select “ITIN or EIN application” and use the brief above for your summary. Your preferred time is a request; KBA will confirm availability and agree the service scope separately.
US federal ITIN application guidance checked against the linked IRS sources on 8 September 2026. This guide is for UK-based applicants; the relevant tax year and application requirements depend on your circumstances.