Employer Identification Number (EIN)
The IRS-issued nine-digit federal tax ID for a business — effectively an SSN for the entity. It identifies the business on its federal tax returns and information returns. Issued by the IRS, free of charge.
What employer identification number (ein) means.
An Employer Identification Number (EIN) is the nine-digit federal tax ID the IRS assigns to a business or other entity — in effect a Social Security number for the entity — and it identifies the business on its federal tax returns and information returns.
The IRS Instructions for Form SS-4 (Rev. December 2025) define it: “An EIN is a 9-digit number (for example, 12-3456789) assigned to sole proprietors, corporations, partnerships, estates, trusts, and other entities for tax filing and reporting purposes.” The IRS issues it directly and free; its Get an EIN page says “You never have to pay a fee for an EIN.” This page is educational; whether your business needs one, and any entity or tax question around it, belongs with the IRS and your CPA or EA.
Where the EIN shows up in your books.
The IRS lists when a business generally needs one, including to “Hire employees,” “Operate a partnership or corporation” and “Change business structures or ownership.” In the books, the EIN is the thread that ties the records together: it is on the payroll filings, on the W-9 the business gives its own customers, and on every information return it files.
What TechBrot does is operational: making sure the EIN is recorded correctly in QuickBooks and that payroll and the books are set up under the right one — see payroll management. Obtaining the EIN, and any entity or tax decision behind it, is handled directly with the IRS and your CPA or EA. TechBrot does not prepare or file tax returns; we work with your CPA or EA.
An EIN change in QuickBooks: a worked example.
Illustrative details, not a client file.
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The change
Take a sole proprietor who has run payroll under an EIN and forms an LLC on July 1 that is taxed as an S corporation. The new entity has its own EIN, so from July 1 payroll runs under the new number, and the company settings, the payroll setup and the W-9 the business gives its customers all change on that date.
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What the books show
January to June: wages, payroll liabilities and deposits under the old EIN. July to December: the same under the new one, with its own payroll tax filings. The new entity’s bank account, opening balances and equity start on July 1, so each EIN’s records stand on their own.
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Why it matters at year end
Each EIN issues its own year-end forms for its own months. A payroll run under the wrong number mid-year leaves W-2s and quarterly filings that do not match the books, which is far harder to put right in January than in July.
How an EIN goes wrong in QuickBooks.
The owner’s SSN where the EIN belongs
A business that has an EIN uses the owner’s Social Security number on its forms. IRS Publication 583 is direct: “Do not use your social security number as a substitute for an EIN on your tax returns.”
One file, two entities
After an entity change the old and new businesses share one QuickBooks file with no cut-over date, so payroll, bank activity and equity from two EINs run together.
A second EIN by accident
Applying again instead of finding the original number. The SS-4 instructions say to use only one application method for each entity “so you don’t receive more than one EIN for an entity.”
Set up once, in the right order
Entity, EIN, bank accounts, chart of accounts and opening balances in the right order is TechBrot’s new business setup. The EIN application itself is yours, made directly with the IRS.
EIN (federal) vs. a state tax ID.
They’re different numbers from different authorities. The EIN is federal, issued once by the IRS, and identifies the business to the federal government. A state tax or registration ID is issued separately by a state — for state payroll withholding, sales tax, or business registration — and a business operating in several states may hold more than one. Having an EIN does not give you a state ID, and vice versa.
Employer Identification Number (EIN) questions.
Does it cost anything to get an EIN?
No. The IRS says “You never have to pay a fee for an EIN” and warns “Beware of websites that charge for an EIN.” You apply directly with the IRS.
Can I use my Social Security number instead of an EIN?
Not where the business is required to have an EIN. IRS Publication 583 says “Do not use your social security number as a substitute for an EIN on your tax returns.” Whether your business needs one is confirmed from the IRS guidance and with your CPA or EA.
Payroll or books not lined up to the right EIN?
A QuickBooks ProAdvisor confirms your EIN is recorded correctly in QuickBooks and that payroll and the books are configured to it — fixed-fee, in writing. The IRS issues the EIN; your CPA advises.
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