How to Get a Tax ID Number in Idaho for a New Business

To get a tax ID number for a new business in Idaho, first identify which number you need. A federal Employer Identification Number (EIN) comes from the Internal Revenue Service. Idaho tax permits and account numbers are obtained separately through Idaho Business Registration (IBR). Depending on the business, you may need an EIN, one or more Idaho tax accounts, or both.

Complete the steps in the right order: establish the business entity and register applicable assumed business names with the Idaho Secretary of State, obtain an EIN when required or useful, and then use IBR if the business needs an Idaho tax or employment-related account available through that system. There is not one universal Idaho tax ID that every new business must obtain.

Understand Which Tax ID Number You Need

The phrase “tax ID number” can describe several different identifiers. Knowing the difference prevents a business owner from applying through the wrong agency or assuming that one registration covers every obligation.

Federal EIN

An EIN is a federal tax ID number issued free by the IRS. The IRS requires an EIN for businesses with employees and for entities including partnerships, LLCs, and corporations. A business may also request an EIN for banking or state tax purposes even when federal rules do not otherwise require one.

The EIN identifies the business for federal tax administration. It may also be requested while opening accounts or completing other business registrations, but receiving an EIN does not automatically establish an Idaho tax permit or account.

Idaho tax permits and account numbers

Idaho uses IBR for registrations involving sales or use tax, income-tax withholding, unemployment insurance, specified auditorium district taxes, travel and convention tax, and workers’ compensation-related registration. A business only needs to pursue the accounts connected to its activities.

For example, a business making taxable sales may need to review the Idaho Sales Tax Registration Guide for New Businesses. Tax registration should also be distinguished from licensing. The Business License Requirements in Idaho: State vs Local Explained provides additional context about that separate compliance issue.

Prepare the Business and Required Information

If the business will operate as an LLC, partnership, corporation, or another legal entity, register that entity with the state before requesting its EIN. Idaho also instructs new businesses seeking permits through IBR to register the business and any assumed business names with the Idaho Secretary of State before applying for Idaho tax permits.

Use the exact legal name and other identifying details from the formation records when completing later applications. Consistency is important because similar-looking names, abbreviations, or addresses can make it harder to match the application to the intended entity.

For an IBR application, prepare the following information:

• The business EIN, if one is available.
• Social Security numbers or EINs for owners, partners, and officers, as applicable.
• Business addresses.
• The Idaho start date and incorporation date.
• Relevant information about employees, hiring, and the first paycheck.

Gathering these details before beginning helps the applicant answer questions from the business’s records instead of estimating. It is also useful to decide who is authorized to submit the registration and where confirmation documents should be retained.

Apply for the Federal EIN

After forming the legal entity, determine whether an EIN is required. Businesses with employees and entities such as partnerships, LLCs, and corporations fall within the IRS requirements described above. A sole proprietor without employees may still request an EIN for banking or state tax purposes.

U.S.-based businesses can apply for an EIN online or submit Form SS-4 by fax or mail. The IRS limits applicants to one EIN per day across online, phone, mail, and fax application methods. Choose one method and avoid sending duplicate applications merely because a response has not yet been received.

Before submitting the application:

1. Confirm the legal structure. The selected entity type should agree with the state formation records and the way the owners intend to operate the business.
2. Confirm the legal name. Enter the entity name consistently. If the business uses an assumed name, keep it distinct from the entity’s legal name.
3. Identify the responsible party carefully. Use the person and identifying information appropriate to the business’s ownership and control.
4. Review the application before submission. Check names, addresses, ownership details, and entity classification for typing or selection errors.
5. Retain the resulting record. Keep the EIN confirmation with the formation and tax records rather than relying on memory or an informal note.

The IRS does not charge for issuing an EIN. An EIN application and an Idaho business registration are separate submissions, even when the EIN will later be included on the Idaho application.

Complete Idaho Business Registration When Applicable

Use IBR when the business needs one or more registrations available through that system. Common reasons include sales or use tax activity, paying employees and withholding income tax, unemployment insurance responsibilities, or another listed Idaho program.

Businesses may register online or submit Form IBR-1. The form can be faxed to (208) 334-5364 or mailed to:

Idaho Business Registration
PO Box 36
Boise, ID 83722-0410

Choose a filing method based on the business’s recordkeeping needs and planned start. The Idaho State Tax Commission states that permits generally arrive in 10–15 business days for online applications and can take up to four weeks for mailed applications. No corresponding estimate is stated here for fax filings, so do not assign a delivery date based on the online or mail estimates.

When completing IBR, select only the accounts that match the business’s activities. Review the application for the correct legal entity, ownership information, locations, Idaho start date, and employment details. Save a complete copy of what was submitted, along with later correspondence and permit information.

If sales tax applies, the business may also need to understand how its permit relates to purchasing inventory. The requirements and documentation are discussed in How to Get a Resale Certificate in Idaho.

Avoid Mistakes and Plan the Next Steps

One common mistake is treating an EIN as a substitute for every Idaho registration. The EIN is federal, while Idaho permits and accounts are handled separately. Another is beginning an EIN application for a new legal entity before the entity has been registered with the state. Following the formation, EIN, and Idaho-registration sequence keeps the records aligned.

Also avoid using permits from a prior owner. When a business is purchased, the new owner should apply for new Idaho tax permits because the previous owner’s permits do not transfer. If an existing business changes its legal entity type, it must complete the IBR process again. These events should not be handled merely by changing the name on old permit records.

Other practical safeguards include:

• Do not use the legal entity name and an assumed business name interchangeably.
• Do not submit duplicate EIN applications through different methods.
• Do not request every Idaho account automatically; connect each registration to an actual business activity.
• Do not discard confirmation notices, submitted forms, or permit correspondence.
• Do not assume tax registration resolves state or local licensing questions.

After receiving the relevant identifiers, place them in a secure compliance file with the formation documents. Update bookkeeping, payroll, banking, and invoicing records with the appropriate number, while limiting access to sensitive identifiers. Review the business’s registrations again before adding employees, beginning a new taxable activity, opening another location, changing ownership, or converting to a different legal entity. A change in operations can affect which accounts the business needs even when its name remains the same.