To get a tax ID number in Indiana, you complete two registrations. First, apply to the IRS for a federal Employer Identification Number (EIN), which is free and issued instantly through the online application. Then register your business with the Indiana Department of Revenue using Form BT-1, filed through the state’s INBiz portal, to receive your Indiana Taxpayer Identification Number (TID). The same BT-1 filing signs you up for the specific state taxes you’ll owe, including sales tax, withholding, and any specialty taxes. If you plan to make retail sales, a one-time $25-per-location fee applies for the Registered Retail Merchant Certificate.
Step One: Apply for a Federal EIN
The federal EIN comes first because Indiana’s application generally requires it. The IRS issues EINs at no cost, and the online application takes about ten minutes. You receive the number immediately on approval.1Internal Revenue Service. Get an Employer Identification Number Ignore third-party sites that charge for this. You never have to pay.
The application (Form SS-4) asks for the legal name of the business, the entity type (corporation, partnership, LLC, sole proprietorship), and the reason you’re applying, typically “started a new business” or “hired employees.” You’ll also identify a “responsible party,” the individual who controls or manages the entity. The IRS uses the EIN to track federal income, employment, and excise tax obligations.2Internal Revenue Service. Instructions for Form SS-4
When You Can Skip the EIN
There is one narrow exception. If you’re a sole proprietor or a single-member LLC and you won’t be registering for withholding tax or hiring employees, Indiana lets you use your Social Security Number in place of an EIN. In that case, you have to file a paper BT-1 rather than applying online.3Indiana Department of Revenue. Business Tax Application Checklist for BT-1 Every partnership and corporation, and any business with employees, needs the EIN first.
Applicants Outside the United States
If you have no legal residence or principal place of business in the U.S., the online EIN application isn’t available. You have three options:2Internal Revenue Service. Instructions for Form SS-4
- Phone: call 267-941-1099 (not toll-free), Monday through Friday, 6:00 a.m. to 11:00 p.m. Eastern. Have Form SS-4 completed before you call. The representative assigns an EIN during the call and may ask you to mail or fax the signed form within 24 hours.
- Fax: send the completed SS-4 to 304-707-9471. Include your fax number so the IRS can fax the EIN back, usually within four business days.
- Mail: send SS-4 to Internal Revenue Service, Attn: EIN International Operation, Cincinnati, OH 45999. Allow four to five weeks.
If the responsible party doesn’t have a Social Security Number or Individual Taxpayer Identification Number, enter “foreign” or “N/A” on line 7b of Form SS-4. A duly authorized person, such as a division manager, may sign on behalf of a foreign applicant.
Step Two: Register the Business With Indiana
Form BT-1 is Indiana’s single application for registering a business for all state tax types. Before you start, gather the following:4Indiana Department of Revenue. Form BT-1 Checklist
- Your federal EIN, unless you qualify for the sole-proprietor exception.
- The legal business name exactly as it appears with the Indiana Secretary of State. For corporations, use the name from the corporate charter.
- A six-digit NAICS code describing your primary business activity. Look it up at census.gov/naics. The Department of Revenue uses it to send you relevant tax bulletins and industry guidance.5U.S. Census Bureau. North American Industry Classification System
- The tax types you’re registering for (see below).
- Physical business address and mailing address.
Any mismatch between the BT-1 and your federal or state corporate records can delay the application. Confirm that names, EINs, and entity types line up across every document before you submit.
Choosing Your Tax Types
The BT-1 lets you register for multiple tax types in one filing. The common ones:4Indiana Department of Revenue. Form BT-1 Checklist
- Sales tax. Indiana’s gross retail tax rate is 7%. Any business making retail sales of tangible personal property must register and collect. Registration triggers the $25-per-location fee for a Registered Retail Merchant Certificate.6Indiana General Assembly. Indiana Code 6-2.5-8-1
- Withholding tax. Required if you have employees. Indiana’s state withholding rate is 2.95% for 2026, and most counties add their own rate on top.7Indiana Department of Revenue. How to Compute Withholding for State and County Income Tax
- Out-of-state use tax, for goods bought out of state for use in Indiana when no sales tax was collected at the point of sale.
- Food and beverage tax, in certain counties, for businesses selling food and drinks for immediate consumption. No additional registration fee.
- County innkeeper’s tax, for hotels, motels, and short-term rentals. Rates vary widely by county. No additional registration fee.8Indiana Department of Revenue. County Innkeepers Tax
- Motor vehicle rental excise tax and tire fee, for businesses in those industries.
Check every tax type that applies. Missing one, or registering for the wrong one, means filing an amendment or a separate registration later.
How to Submit the BT-1
Indiana’s preferred method is online registration through INBiz, the state’s business portal at inbiz.in.gov.9Indiana Department of Revenue. Business FAQ You create an account, enter your business information, select your tax types, and pay the $25 Registered Retail Merchant Certificate fee electronically if it applies. The system confirms submission immediately.
To file on paper, download Form BT-1, complete it, and mail it to the Indiana Department of Revenue, P.O. Box 6197, Indianapolis, IN 46206-6197.10Indiana Department of Revenue. Mail in Tax Forms Paper is the only option for sole proprietors using an SSN instead of an EIN. Include a check or money order for the $25 RRMC fee if you’re registering for retail sales.
Processing Times and What You Receive
Online applications filed through INBiz are typically processed within two business days. Once approved, Indiana issues your Taxpayer Identification Number.9Indiana Department of Revenue. Business FAQ The TID is the state-level equivalent of your federal EIN. You’ll use it to file returns, make tax payments, and communicate with the department.11INBiz. Indiana Business Roadmap
Paper applications take four to six weeks.4Indiana Department of Revenue. Form BT-1 Checklist If you’re aiming to open on a specific date, plan around that or use INBiz.
If your application includes retail sales registration, the Department of Revenue issues a Registered Retail Merchant Certificate after processing. You must display it at each registered business location, and you cannot legally make retail sales in Indiana without one.6Indiana General Assembly. Indiana Code 6-2.5-8-1
Remote Sellers Without an Indiana Location
You don’t need a physical location in Indiana to owe Indiana sales tax. If your business sells goods or tangible personal property into Indiana and your gross revenue from those sales exceeds $100,000 in either the current or preceding calendar year, you have to register, collect, and remit the 7% sales tax. Indiana dropped its separate 200-transaction threshold effective January 1, 2024, so the dollar figure is now the only trigger.12Indiana Department of Revenue. Remote Seller FAQs
The registration process is the same BT-1 through INBiz. If you sell through a marketplace like Amazon or Etsy, the marketplace itself may already be collecting and remitting Indiana sales tax on your behalf as a marketplace facilitator. Check with your platform before you register so you don’t double-collect.
After You Have Your TID
Getting the number is the start of ongoing compliance, not the end of it. Once registered, you have to file on schedule even in periods when you owe nothing.
The Department of Revenue assigns your filing frequency (monthly, quarterly, or annually) based on your average monthly tax liability. If your numbers shift significantly, the department adjusts your frequency before the next tax year. Businesses with an average monthly liability above $5,000 have to make payments by electronic funds transfer.9Indiana Department of Revenue. Business FAQ
Missing a filing deadline, even a zero-dollar return, can trigger penalties and put your Registered Retail Merchant Certificate at risk. Treat the compliance calendar with the same care you gave the registration itself.