To fill out Indiana Form ST-105, the state’s general sales tax exemption certificate, complete all five sections on a single page: your purchaser identification and Indiana Taxpayer ID, the seller’s name and address, whether the certificate is blanket or single-purchase along with a description of what you’re buying, the box matching your reason for exemption, and an authorized signature dated and printed with a title. Then hand it to the vendor. The form never goes to the Department of Revenue; the seller keeps it on file as proof the sale was legitimately untaxed.1Indiana Department of Revenue. General Sales Tax Exemption Certificate Form ST-105
One completed ST-105 also covers county innkeeper’s tax and local food and beverage tax on the same transaction, so you don’t need a separate certificate for those.1Indiana Department of Revenue. General Sales Tax Exemption Certificate Form ST-105
Before You Start: Is the ST-105 the Right Form?
The ST-105 is for tangible personal property that falls under a recognized exemption category. It cannot be used for purchases of utilities, vehicles, watercraft, aircraft, or gasoline. Each of those has its own separate exemption form from the Department of Revenue.1Indiana Department of Revenue. General Sales Tax Exemption Certificate Form ST-105
Nonprofits also cannot use this form. A nonprofit must first file Form NP-20A to apply for sales tax exemption, and if approved, the department issues Form NP-1 as the organization’s certificate.2Indiana Department of Revenue. Nonprofit Tax Forms Putting a nonprofit’s name on an ST-105 won’t satisfy a vendor’s records.
Download the current version from the Department of Revenue’s sales tax forms page before filling anything in.3Indiana Department of Revenue. Sales Tax Forms
Section 1: Purchaser Information
Enter your business’s legal name, address, and Indiana Taxpayer Identification Number (TID). The TID is a ten-digit number followed by a three-digit location code (LOC) — the same number you use for Indiana sales and withholding tax reporting.1Indiana Department of Revenue. General Sales Tax Exemption Certificate Form ST-105
If you don’t have a TID, use one of these substitutes:
- Out-of-state purchasers without an Indiana TID: enter your home state’s business license number or state-issued ID number.
- Federal government agencies: enter your Federal ID Number (FID/EIN) in the State ID Number field.
- Farmers: enter your Social Security Number or FID. You must also complete Form AGQ-100, the Agricultural Equipment Exemption Usage Questionnaire, to determine whether your purchase qualifies for a full or predominant-use exemption. If the questionnaire shows the purchase doesn’t qualify, don’t issue an ST-105. Pay the tax at the register and file Form GA-110L (Claim for Refund) afterward.
- Public transportation haulers operating under another carrier’s authority or a school bus contract: enter your SSN or FID and include your USDOT number in the exemption reason area.
Section 2: Seller Information
Write in the vendor’s legal name and business address. This is what ties the certificate to a specific seller. If you’re setting up tax-exempt buying with multiple vendors, you need a separate certificate for each one.
Section 3: Blanket or Single Purchase, and Description
Check one box. A blanket certificate covers all future qualifying purchases from that vendor, so you don’t have to submit a new form each time you order. A single-purchase certificate covers one transaction, which fits a one-time buy from a vendor you don’t regularly work with.
Below the checkbox, describe the type of property you’re buying. Keep it accurate to the exemption you’re claiming — “raw materials for resale,” “manufacturing machinery,” “seed and fertilizer,” and so on.
Section 4: Reason for Exemption
Check the box that matches why the purchase is exempt. The categories printed on the form are:
- Sales to a retailer, wholesaler, or manufacturer for resale only.
- Sales of manufacturing machinery, tools, and equipment to be used directly in direct production.
- Sales to nonprofits (note: this line exists on the form, but as covered above, nonprofits should use Form NP-1, not the ST-105).
- Sales of tangible personal property predominantly used (more than 50%) in providing public transportation.
- Sales to persons occupationally engaged as farmers, to be used directly in production of agricultural products for sale.
- Sales to a contractor for exempt projects such as public schools, government, or nonprofit facilities.
- Sales to Indiana governmental units — agencies, cities, towns, municipalities, public schools, state universities.
- Sales to the United States federal government (list the agency).
- Other — check and describe if none of the above fit.
Two of these boxes cause most of the confusion:
Resale. This only applies to items you buy with the sole intent of reselling them. Office supplies, breakroom coffee, and equipment you use to run the business don’t qualify, even if you’re a retailer. If you pull an item out of resale inventory and use it internally, you owe Indiana use tax on it.
Manufacturing. The exemption covers machinery, tools, and equipment acquired for direct use in direct production, manufacture, fabrication, assembly, extraction, mining, processing, refining, or finishing of other tangible personal property. The equipment has to physically participate in making the product. Support items like office furniture in a manufacturing plant don’t qualify. Commercial printing, tire retreading, and tree felling for further production count as manufacturing under the statute.4Indiana General Assembly. Indiana Code 6-2.5-5-3 – Exemption; Acquisition for Direct Use in Direct Production
Agricultural production. Farmers claim exemptions on animals, feed, seed, plants, fertilizer, insecticides, fungicides, and other property used directly in producing food or commodities for sale. The buyer has to be occupationally engaged in that production.5Justia Law. Indiana Code Title 6 – Article 2.5 – Chapter 5 Remember the AGQ-100 step for equipment purchases.
Section 5: Signature
An authorized representative of the purchaser signs and dates the form and prints their name and title. The signature line is a certification made under penalties of perjury that the purchase qualifies for exemption under the State Gross Retail Sales Tax Act (Indiana Code 6-2.5).1Indiana Department of Revenue. General Sales Tax Exemption Certificate Form ST-105
Every section has to be complete. If any of the five is left blank, the certificate is invalid and the seller becomes responsible for collecting the tax. A vendor who accepts a half-finished form loses the legal protection a valid certificate would have provided.1Indiana Department of Revenue. General Sales Tax Exemption Certificate Form ST-105
Give It to the Vendor and Keep a Copy
The completed ST-105 goes to the seller, not to the state. Deliver it at the time of the transaction, or when you first open a business account with the vendor. Many sellers accept scanned copies by email; others want a physical original. Once the certificate is on file, the seller can point to it as evidence that tax was not owed, and the burden of justifying the exempt use falls on you if the state audits the transaction.
Indiana Code 6-8.1-5-4 requires tax records, including exemption certificates, to be kept for at least three years after the final payment of the tax liability was due. Hold them longer if a judicial proceeding or appeal related to the tax is still open.6Indiana General Assembly. Indiana Code 6-8.1-5-4 – Books and Records; Federal Returns; Inspection Both buyer and seller should keep copies.
The ST-105 doesn’t have a printed expiration date, but the information on it has to remain accurate. If your business changes its legal name, moves, or goes through an ownership change, issue a new certificate to every vendor that has your old one. Sellers commonly ask for refreshed certificates every few years to confirm buyer status is current. If you can’t produce a valid certificate during an audit, the state can assess back taxes plus interest on the transactions the certificate was supposed to cover.
What Happens If You Use It Incorrectly
The signature block warns that misuse of the certificate, whether negligent or intentional, can result in unpaid tax, interest, civil penalties, and criminal penalties against you personally and against the business you represent.1Indiana Department of Revenue. General Sales Tax Exemption Certificate Form ST-105 The certification is under penalty of perjury.
The most common audit problem is a buyer who claimed resale but never actually resold the goods. If you buy something tax-free on an ST-105 and then divert it to a non-exempt use, you owe Indiana use tax on that item. Reporting and paying the use tax is straightforward; claiming an exemption you weren’t entitled to is what the misuse language on the form is aimed at.