Indiana Form ST-105, the state’s General Sales Tax Exemption Certificate, has five sections, and every one of them must be completed for the certificate to be valid. These Indiana ST-105 instructions walk through each section in order, along with the rules that decide whether the seller can actually honor the exemption once you hand it over. Skip a field and the seller has to collect the full seven percent sales tax as if you had never presented the form at all.1Indiana Department of Revenue. Indiana General Sales Tax Exemption Certificate Form ST-105
Download the current version from the Indiana Department of Revenue’s sales tax forms page at in.gov. It’s a fillable PDF, so you can type into it before printing.2Indiana Department of Revenue. Sales Tax Forms Out-of-state purchasers who work within the Streamlined Sales and Use Tax Agreement can substitute SSTGB Form F0003, but for most Indiana transactions the ST-105 is the form.
Section 1: Purchaser Information
Start with the purchaser’s legal business name and full physical address. Below that, the form needs at least one identifying number.
For an Indiana business, that means the ten-digit Taxpayer Identification Number (TID) the Department of Revenue issued for sales or withholding tax, together with the three-digit location (LOC) number printed on your Registered Retail Merchant’s Certificate.3Indiana Department of Revenue. Withholding FAQ If you’re an out-of-state purchaser with no Indiana TID, the form accepts a state tax ID number, a business license number, or a state-issued ID number from your home state.1Indiana Department of Revenue. Indiana General Sales Tax Exemption Certificate Form ST-105
One narrow exception. Purchasers claiming the public transportation exemption who haul under someone else’s motor carrier authority, or who hold a school bus operator contract, must give a Social Security Number or Federal ID Number instead of a state ID.
Section 2: Seller Information
Fill in the seller’s legal name and address. It feels redundant, since the seller already knows who they are, but the certificate is a standalone document that has to make sense on its own face if an auditor pulls it years later. Don’t leave it blank.
Section 3: Single Purchase or Blanket Certificate
Check one of two boxes. A single-purchase certificate covers one specific transaction, and you describe the items on that sale in the space provided. A blanket certificate stays on file with the seller and covers all future purchases that fall within the same exemption. For businesses that buy from the same vendor repeatedly, a blanket certificate is the practical choice because it avoids repeating the paperwork on every order.
Even on a blanket certificate, fill in the description-of-items field. Write something concrete, like “raw steel for manufacturing” or “packaging materials for resale.” Generic entries such as “various items” attract audit questions you don’t want to answer later.
Section 4: Exemption Category
Check the single box that matches the legal basis for the exemption. The categories on the form are:
- Resale, for retailers, wholesalers, or manufacturers buying goods only to resell them.
- Manufacturing equipment, meaning machinery, tools, and equipment for direct use in production, fabrication, assembly, processing, or finishing of tangible personal property.4Indiana General Assembly. Indiana Code 6-2.5-5-3 – Exemption; Acquisition for Direct Use in Direct Production
- Public transportation, for property used more than 50 percent of the time providing public transportation; you must supply your USDOT number.
- Agricultural production, for machinery, tools, and equipment used directly in producing, extracting, harvesting, or processing agricultural commodities, purchased by someone occupationally engaged as a farmer.5Indiana General Assembly. Indiana Code 6-2.5-5-2 – Agricultural Machinery, Tools, and Equipment Exemptions
- Contractor for exempt projects, covering sales to a contractor working on projects for public schools, government entities, or nonprofits.
- Indiana governmental units, including agencies, cities, towns, municipalities, public schools, and state universities.
- United States Federal Government, where you must write in the agency name.
- Other, for any exemption not listed; you have to write in an explanation and cite the relevant statute.
Pick only one. If more than one theory could apply, pick the most specific. “Other” is a real option, but the written explanation needs to be detailed enough that an auditor can evaluate the claim without calling you.
Section 5: Certification and Signature
Sign and date the form. Your signature certifies, under penalty of perjury, that the goods are being purchased for an exempt purpose under Indiana sales tax law, and it confirms the item is not a utility, vehicle, watercraft, or aircraft (those have their own exemption forms). It also acknowledges that negligent or intentional misuse of the certificate can result in the tax being assessed against you personally or your business, plus interest and civil or criminal penalties.1Indiana Department of Revenue. Indiana General Sales Tax Exemption Certificate Form ST-105
Who Cannot Use Form ST-105
Two groups often reach for this form and shouldn’t. Nonprofit organizations cannot use the ST-105. The certificate itself states that it may not be issued by a nonprofit, and the purchaser has to attest that the purchase is not being made by one.1Indiana Department of Revenue. Indiana General Sales Tax Exemption Certificate Form ST-105 Indiana nonprofits get their sales tax exemption a different way: after IRS recognition, they file Form NP-20A through INTIME, and once approved they receive Form NP-1 to present to sellers. Registration is renewed by filing Form NP-20R every five years by May 15.6Indiana Department of Revenue. Nonprofit Tax Forms
Individual consumers buying things for personal use also cannot use the ST-105. The form is built for business-to-business purchases tied to an exempt purpose, and using it to dodge tax on personal shopping is exactly what the perjury clause is aimed at.
Government purchases deserve a note here. Direct purchases by the U.S. federal government, its agencies, and instrumentalities are exempt, and so are state and local government purchases when the invoice is billed to the government entity itself.7Indiana Department of Revenue. Sales Tax Information Bulletin 4 A government employee who buys something out of pocket and gets reimbursed does not qualify. They pay the tax at the register like anyone else.
What the Seller Does With the Certificate
Hand the completed form to the seller at or before the transaction. It does not get mailed to the Department of Revenue. The seller keeps it in their business records.1Indiana Department of Revenue. Indiana General Sales Tax Exemption Certificate Form ST-105
Sellers must retain these records for at least three years after the final payment of the related tax liability was due, which is Indiana’s general record-retention period for tax documents. The retention period becomes unlimited if the Department opens a fraud investigation or if the seller filed a suspected fraudulent return, and it extends whenever a related judicial proceeding or appeal is pending.8Indiana General Assembly. Indiana Code 6-8.1-5-4 – Duty to Maintain Books and Records Without a valid certificate on file, the seller has to charge the full seven percent.9STATS Indiana. About Indiana Retail Sales and Use Taxes
What Happens if a Field Is Blank
Certificates sometimes reach the seller with a missing entry. Indiana law gives the seller 90 days after the sale to obtain either a fully completed certificate or the specific data needed to complete it. Miss that window and the exemption is not valid; the seller owes the tax.10Indiana General Assembly. Indiana Code 6-2.5-8-8 – Exemption Certificates
If the Department later audits the transaction and asks the seller to substantiate the exemption, the seller has 120 days from the Department’s request to produce a fully completed certificate or otherwise prove the transaction was genuinely exempt.10Indiana General Assembly. Indiana Code 6-2.5-8-8 – Exemption Certificates From a purchaser’s standpoint, the practical takeaway is simple: fill every field the first time, because the seller who has to chase you down for a missing TID after the fact may just charge the tax and move on.
Penalties for Misusing the Certificate
Both sides of the transaction carry exposure. A purchaser who signs a fraudulent certificate faces the assessed tax, interest, and civil or criminal penalties, and the certification language on the form is written to cut off any “I didn’t know” defense.1Indiana Department of Revenue. Indiana General Sales Tax Exemption Certificate Form ST-105
On the seller side, a merchant, or an officer, employee, or member of a corporate or partnership merchant with a duty to collect and remit sales tax, holds that tax money in trust for the state. Knowingly failing to collect or remit is a Level 6 felony in Indiana.11Indiana General Assembly. Indiana Code 6-2.5-9-3 – Personal Liability of Holder of Taxes in Trust; Failure to Collect and Remit; Offense Even setting felony exposure aside, back taxes, interest, and penalties compounded across a series of undocumented sales can add up fast for a small business, which is why sellers who take exemption certificates seriously ask for a properly completed ST-105 every time.