Your own personal tax ID number, for yourself, is your Social Security number.
If you have a business that is a sole proprietorship, and you obtained from the IRS an Employer ID Number (EIN) for the business, the EIN should be on line D of Schedule C. The EIN is the tax ID number for the business. Many small sole proprietorships do not have an EIN. If your sole proprietorship does not have an EIN, then your Social Security number is also the tax ID number for the business.
Why are you looking for your tax ID number?
