A UI account number is a state-issued identifier that connects your business to an unemployment insurance tax account with a specific state workforce agency. You get one by registering as an employer with that agency, usually online, once you cross the state’s threshold for unemployment tax liability. Every state assigns its own number, so if you have employees in more than one state, you’ll have more than one UI account number. The number follows your business through every quarterly wage report, tax payment, and unemployment claim a former worker files.
How It Differs From Your EIN
Your Federal Employer Identification Number is issued by the IRS and identifies your business for federal tax purposes.1Internal Revenue Service. Employer Identification Number A UI account number is something separate. It’s assigned by a state workforce agency and used only for unemployment insurance in that state. One business has one EIN but can hold several UI account numbers.
The two numbers travel on different forms. Your EIN appears on federal filings like Form 940 (annual federal unemployment tax) and Form 941 (quarterly payroll tax). Your UI account number appears on state quarterly wage reports and state unemployment tax payments. Putting one where the other belongs is a common cause of rejected filings.
When You Need to Register
Federal law sets the baseline. Under the general test, you owe federal unemployment tax, and will need to register with your state, if you paid $1,500 or more in wages during any calendar quarter, or if you had at least one employee for any part of a day during 20 or more different weeks in a year.2Internal Revenue Service. Topic No. 759, Form 940 – Employer’s Annual Federal Unemployment (FUTA) Tax Return Most small businesses with even one part-time worker will hit one of those triggers fairly quickly.
Different rules apply to household and farm employers. Household employers (a nanny, housekeeper, or home health aide) become liable at $1,000 or more in cash wages in any calendar quarter. Agricultural employers face a higher bar: $20,000 or more in wages in any quarter, or 10 or more farm workers on at least one day in each of 20 different weeks.3U.S. Department of Labor. Unemployment Insurance Tax Fact Sheet
State thresholds sometimes differ from the federal standard. Some states impose liability sooner or cover categories of workers that federal law excludes, so check the workforce agency in each state where you have employees. Once you cross the threshold in a state, you need a UI account number for that state.
How to Get a UI Account Number
Registration happens through each state’s unemployment insurance agency. Depending on the state, it may go by the department of labor, department of employment services, or employment security commission. Nearly every state now offers online registration through an employer portal, though some still accept paper forms.
You’ll typically be asked for:
- Your Federal Employer Identification Number.
- Your business structure: sole proprietorship, LLC, corporation, partnership, or nonprofit.
- Owner or officer information, including names, addresses, and Social Security numbers for individuals with ownership stakes.
- Your NAICS industry code.
- Payroll details: date of first payroll, number of employees, and sometimes estimated quarterly wages.
After the state reviews your submission, it determines whether you’re liable for unemployment contributions. If you are, you’ll receive your UI account number along with your initial tax rate. Most states finish this within a few weeks, though processing times vary. Keep the confirmation notice; it’s the easiest place to find your number later.
Finding a Number You Already Have
If you’ve registered before but can’t locate the number, check these sources first:
- The initial determination letter your state sent when it confirmed your liability and assigned the account.
- Your annual tax rate notice. States mail these each year, and the UI account number appears near the top.
- Any previously filed quarterly wage report.
- Your state’s online employer portal, where account details are usually visible after login.
- Your payroll provider, if you use one. They have the number on file because they need it to file your state reports.
The format varies by state. Some assign six-digit numbers, others use eight or more digits, and a few include letters or dashes. If none of these sources turn it up, call your state’s unemployment tax division. They can look it up using your FEIN.
What the Number Controls Once You Have It
Your UI account number is more than a filing reference. It’s the container for your unemployment claims history, and that history determines how much you pay in state unemployment tax through a system called experience rating. The more claims former employees successfully file against your account, the higher your rate climbs. Fewer claims mean a lower rate over time.4U.S. Department of Labor. Experience Rating
New employers have no claims history, so every state assigns a standard starting rate. These initial rates vary widely, with some states starting new employers around 1% and others above 3%. You’ll keep that initial rate for roughly two to three years until the state can calculate a rate from your actual experience. Federal law requires at least three consecutive years of experience before a state can assign a reduced rate.4U.S. Department of Labor. Experience Rating
State unemployment tax applies only up to a capped amount of each employee’s annual wages, known as the taxable wage base. The federal minimum is $7,000 per employee per year.2Internal Revenue Service. Topic No. 759, Form 940 – Employer’s Annual Federal Unemployment (FUTA) Tax Return A handful of states use that $7,000 floor, but most set their own base higher. For 2026, state wage bases range up to roughly $78,000 in the highest-cost states.
Responding to Claims Filed Against Your Account
When a former employee files for unemployment benefits, the state uses your UI account number to identify you and sends you a notice. You then have a limited window, typically 10 to 14 days depending on the state, to respond with any information that might affect the claim. Ignoring the notice or responding late generally means you lose the right to contest the claim, and the benefits get charged to your account anyway. Those charges feed directly into your experience rating and push your future tax rate up.
Closing or Transferring the Account
If you shut down or no longer have employees, formally close your UI account with each state where you’re registered. Otherwise the state keeps expecting quarterly reports, and missing those filings can trigger penalties even when you owe no tax. Most states let you close the account through the same employer portal you used to register, or by submitting a change request form. You’ll still need to file final quarterly reports covering any period during which you had employees.
When one business acquires another, the UI experience rating account often transfers with the workforce. In a full acquisition, the seller’s account is typically closed and its entire experience merges into the buyer’s account. In a partial acquisition, experience transfers proportionally based on the share of payroll or employees that moved.5U.S. Department of Labor. Transfers of Experience Benefits paid to former employees of the acquired business get charged to the successor going forward, which is worth checking during due diligence.