Form W-7
IRS, Application for an ITIN
The application for an individual taxpayer identification number, for people who need a US tax number but cannot get an SSN.
What is Form W-7?
Form W-7 applies for an ITIN, a nine-digit number the IRS issues to people who need a US taxpayer number but are not eligible for a Social Security number. In US-UK families the usual case is a British spouse on an American's joint return. The number exists for tax purposes only.
Getting a US tax number without an SSN
An ITIN is needed whenever a US tax return or information form must show a person's taxpayer number and that person cannot obtain an SSN.
The most common case in our work is a non-US spouse when a couple elects to file jointly. Others include dependants claimed on a US return, nonresidents who must file Form 1040-NR, and people claiming a treaty benefit where a number is required.
The application is generally submitted with the tax return that requires the number, rather than on its own. The IRS then processes the return once the number is issued, which can delay any refund. Certain exceptions allow an application without a return, for example where a number is needed for a third party's reporting. The rules on supporting documents and certification are strict and change from time to time.
An ITIN does not give a right to work in the US, eligibility for Social Security benefits or immigration status. It is also not valid for every credit, and some credits require an SSN. A number that is not used on a federal return for several consecutive years expires and must be renewed with a new Form W-7 before it is used again.
At a glance
- The IRS, usually alongside the tax return
- Filed with
- A nine-digit individual taxpayer identification number
- Issues
- After several consecutive years without use on a return
- Expiry
- Work authorisation or Social Security eligibility
- Does not give
Figures are for the tax year stated in the official instructions linked below.
How we handle it
- Individual Tax Returns
US federal returns for Americans living in the UK and British nationals with US income, prepared with the UK figures in view.
- Cross-Border Tax
US and UK returns prepared together from one set of workpapers, so credits, tax years and exchange rates line up across both.
- Cross-Border Property
US and UK tax on homes and rental property held across the two countries, including sales, currency gains, FIRPTA and UK reporting.
Where people go wrong
The Form W-7 errors we correct most often.
Who files it
- Non-US spouses of American citizens when the couple files a joint return
- British children and dependants claimed on a US parent's return
- Nonresidents filing Form 1040-NR for US rental or business income
- Former ITIN holders whose number expired after years of non-use
01
Applying separately and then filing the return without waiting for the number
02
Letting an ITIN lapse and then filing a return that relies on it
03
Assuming an ITIN qualifies for credits that require a Social Security number
04
Applying for an ITIN for someone who is eligible for an SSN
Why US UK Tax Returns
Every form is prepared against the official instructions, and every position on it is one we can point to in the Code, the treaty or HMRC's guidance.
One File
US and UK returns prepared in the same engagement and reconciled line by line.
Primary Sources
Every position traced to the Code, the treaty, IRS instructions or HMRC guidance.
Scope First
Returns, forms, years and fee agreed in writing before work begins.
The Same People
The team that files this year carries the elections and credits into the next.
Questions we are asked
My British husband has no US number. Can we still file jointly?
Yes, if you elect to treat him as a US resident for the year, and he obtains an ITIN. The Form W-7 is normally sent with the joint return. Whether joint filing makes sense is a separate question, because the election brings his worldwide income into the US return. That should be modelled before applying.
Does my UK spouse need an ITIN if I file married filing separately?
Not always. On a separate return, the spouse's taxpayer number is requested, but the IRS allows a nonresident spouse without one to be identified in another way. An ITIN becomes necessary mainly when the couple elects to file jointly, or when the spouse has a US filing obligation of their own. The right approach depends on the filing status chosen and on the spouse's own US income.
Does an ITIN give me any immigration status?
No. An ITIN is used only for federal tax reporting. It does not authorise work in the US, does not make someone eligible for Social Security benefits and does not affect immigration status. Its only function is to let the IRS match returns and payments to a person who has no Social Security number.
Primary sources
What this page says is drawn from the official material below. Read it yourself; we would rather be checked than trusted.
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