What is a TIN?

Your Taxpayer Identification Number, or TIN, is the number the IRS assigns to you for tax purposes. If you are an individual, your TIN is your Social Security Number (SSN). If you are a business, your TIN is your Employer Identification Number (EIN), which is issued by the IRS.

If you’re unsure of your TIN, you can find it on your Social Security card, tax returns, or official IRS correspondence. If your business has an EIN, you may have received it when registering your company or applying for tax-related purposes.