An Indiana sales tax audit is an examination by the Indiana Department of Revenue (DOR) of whether your business correctly collected, reported, and paid Indiana sales tax and use tax. If you receive an audit notice, note every response date, preserve the records for the periods identified, and contact the auditor using the details in the notice. If DOR later issues a proposed assessment and you disagree, you generally have 60 days from the date printed on it to file a written protest; do not treat an audit notice and a proposed assessment as the same document.
Sales Tax Compliance USA is a done-for-you service staffed by people. We help ecommerce and cross-border sellers organize records, understand audit findings, prepare a response, and work through the protest process. Indiana uses one statewide sales tax rate and has no local sales tax, so rate calculation is straightforward once registered; the harder audit questions are often whether a transaction is taxable, where it belongs, whether tax was collected or paid, and whether the records support the return.
What to do when you receive an Indiana audit notice
Read the notice carefully and identify the tax type, periods under review, records requested, auditor contact information, and response deadline. Confirm that the notice concerns your business and preserve the original notice and any envelope or electronic message. Do not ignore it, and do not assume that a request for records is itself a final assessment.
Contact the auditor promptly if the request is unclear, records are held by a marketplace or bookkeeper, or you need to discuss how to provide the material. Keep a written record of communications and submit organized copies rather than altering original records. If the notice proposes an assessment, calendar the protest deadline immediately: the Indiana Department of Revenue says a written protest must be filed within 60 days of the date printed on the proposed assessment, and that statutory deadline cannot be extended.
Before sending a substantive response, reconcile the requested periods to your filed returns, sales channels, and accounting records. If the potential exposure is significant or the issues are complicated, get help early so that explanations and supporting documents are consistent. A service provider can help coordinate the response, but the business remains responsible for meeting the notice’s deadlines.
What happens during an Indiana sales tax audit?
The Indiana Department of Revenue examines records to determine whether the business complied with Indiana gross retail (sales) and use tax requirements. The auditor may compare filed returns with sales reports and transaction records, review how the business treated taxable and exempt sales, and examine purchases to see whether sales tax was paid to vendors or use tax was reported. The scope and procedures depend on the notice and the facts of the business.
Expect questions about how orders were recorded, how refunds and cancellations were handled, what documentation supports claimed exemptions, and how tax was treated on business purchases. For an ecommerce seller, the auditor may need to understand the relationship between order data, marketplace reports, payment processor deposits, shipping records, and the general ledger. A difference between a sales report and a tax return is not automatically proof of unpaid tax; explain the difference and support it with records.
The auditor may request additional information and discuss preliminary findings. If DOR determines additional tax is due, it can issue an audit report summary and a Notice of Proposed Assessment. Review the calculation and the periods covered before deciding whether to pay, seek clarification, or protest. The audit process and any response dates are specific to the notice; follow the dates DOR gives you.
How far back can Indiana audit sales tax returns?
Indiana’s assessment time limit depends on the circumstances, including whether returns were filed and whether a written agreement extends the period. DOR’s audit manual instructs auditors to identify periods that remain open under the statute of limitations and notes that DOR and a taxpayer may agree in writing, before the period expires, to extend the time for proposing an assessment or claiming a refund.
Because the applicable period can turn on filing history and other facts, do not assume that every audit reaches back the same number of years. Check the periods listed in the notice and ask DOR to explain the basis for any period you believe is outside the applicable limit. Before signing an extension, understand which periods it covers and what time it adds; get qualified advice if you are unsure.
Which records should you gather for an Indiana sales tax audit?
Start with the records named in the notice. Commonly useful materials include filed sales tax returns and payment confirmations; transaction-level sales exports; invoices and order details; marketplace and payment processor reports; refund, cancellation, and chargeback records; shipping and delivery documentation; exemption certificates and customer correspondence; and general-ledger or accounting reports that reconcile sales to returns.
Also gather purchase invoices, vendor statements, and evidence of sales tax paid or use tax reported on business purchases. DOR identifies purchase records as relevant to checking whether tax was paid on taxable purchases. For cross-border sellers, retain records that explain the seller of record, the sales channel, the customer and delivery information, and how each transaction was classified for Indiana reporting.
Provide a clear index and explain how the files fit together. If a requested record does not exist or is held by a third party, say so promptly and identify what alternative evidence is available. Do not create backdated documents or change source data; preserve the original files and explain any corrections separately.
How to protest an Indiana sales tax assessment
You can challenge a proposed assessment by filing a written protest with the Indiana Department of Revenue. DOR requires the protest within 60 days of the date printed on the proposed assessment; the deadline is statutory and cannot be extended. The protest should explain the specific reasons you disagree and include the Protest Submission Form and supporting documentation.
DOR accepts protests through INTIME, its Indiana Taxpayer Information Management Engine, and by mail to the address listed on its appeals page. For an INTIME submission, DOR’s protest guide says you need the Letter ID from the notice. Check the current DOR instructions and the notice itself for the correct submission method and address, and retain proof of timely filing.
Make the protest specific: identify the disputed periods, transactions, calculations, or legal treatment, and connect each point to evidence. If you agree with part of the assessment but dispute another part, state that distinction clearly. A protest is not simply a request for more time; it is your opportunity to explain why the proposed amount is incorrect.
How Indiana sales tax audit appeals work
The administrative process begins with a written protest of a proposed assessment. You may request a hearing as part of the protest process. DOR considers the protest and evidence and issues a Letter of Findings; the hearing is an opportunity to present information, not a settlement conference. DOR’s appeals materials describe a further appeal to the Indiana Tax Court if you disagree with the administrative decision, subject to the applicable court deadlines and procedures.
Do not assume that filing a protest automatically resolves collection or stops interest from accruing. The effect of a protest, payment, or court action depends on the stage of the case and the applicable rules. Read DOR’s current appeal instructions and the assessment notice, and get legal advice about court proceedings or collection risk. A tax attorney can represent a business in an audit and related proceedings; confirm the attorney’s role and representation arrangements directly with them.
Keep the administrative record complete: preserve the protest, attachments, delivery confirmation, hearing materials, correspondence, and DOR’s decision. If DOR requests more information, respond by the stated date and explain any remaining gaps. Missing a deadline can limit the available options, so seek help promptly if you receive an adverse decision.
Options for resolving an Indiana sales tax liability
If you agree with an assessment, paying it can resolve the balance, but check the bill for the amount due and payment instructions. If you disagree, use the protest process rather than letting the bill go unanswered. If you cannot pay in full, DOR provides payment-plan options through INTIME for eligible liabilities. Eligibility, required payment terms, and the effect on penalties and interest depend on the account; confirm the current terms with DOR before relying on a plan.
DOR states that a payment plan does not prevent a 10% penalty from being incurred and that interest continues to accrue until the tax debt is paid in full. A plan addresses payment, not whether the assessment is correct. If you dispute the amount, consider the protest deadline while separately discussing payment or collection options with DOR.
Where the audit identifies unfiled returns or broader registration and reporting issues, address those as well as the bill. DOR’s sales tax information explains that unresolved liabilities and unfiled returns can affect a business’s Retail Merchant Certificate. The right resolution depends on the account history and current DOR rules, so verify the available options for your specific case.
Potential penalties and interest after an audit
An audit assessment may include tax, penalties, and interest. DOR’s collection information states that a 10% penalty may still be incurred on a payment-plan balance and that interest continues to accrue until the tax debt is paid in full. The amount and treatment can depend on the tax type, the reason for the assessment, and the account facts; review the calculation on the notice rather than assuming a standard total.
If you believe a penalty or calculation is wrong, identify the disputed item and explain why in your written protest. DOR allows taxpayers to protest a proposed assessment, including a penalty dispute, through its appeals process. Ask DOR to show how it calculated the balance and verify current rates and rules with the department, since interest and other amounts can change over time.
How sales tax obligations can lead to audit exposure
Sales tax audit exposure can arise when a business makes taxable Indiana sales but does not register, collect, report, or remit tax as required. It can also arise from return-to-ledger differences, unsupported exemption treatment, incomplete transaction records, or taxable business purchases for which neither sales tax nor use tax was paid. DOR’s audit manual describes its review of sales reports and records and its examination of purchases for sales or use tax compliance.
Indiana’s statewide rate and lack of local sales taxes simplify rate calculation once a seller is registered, but they do not decide whether a particular product or transaction is taxable or whether the seller has an obligation to collect. Ecommerce and cross-border sellers should review their sales channels, transaction classifications, purchase records, and filing history. Registration and filing are handled through DOR systems including INTIME; confirm current requirements with DOR for your business circumstances.
Sales Tax Compliance USA provides hands-on support for sellers facing an Indiana audit. Our people can help organize records, reconcile sales data to returns, prepare explanations, coordinate communications, and assemble protest materials. We do not promise a particular audit result; the appropriate strategy depends on the notice, evidence, and applicable Indiana rules.
Not sure how this applies to your business? We handle US sales tax registration, filing and remittance for ecommerce sellers as a fully managed service, for one fee. Book a free consultation and we will review your own position with you.
Indiana sales tax audit: how common transaction and record categories differ in an audit review
| Category | What the auditor may check | Useful evidence |
|---|---|---|
| Indiana customer sale | Whether the transaction was reported and Indiana tax was collected or otherwise accounted for | Order detail, invoice, delivery information, return entry, and payment record |
| Marketplace or other sales channel | Whether channel reports reconcile to the business’s returns and whether the seller’s records explain the transaction treatment | Marketplace settlement and transaction exports, order records, and reconciliation to the ledger |
| Refund, cancellation, or chargeback | Whether the reported sales adjustment is supported and reflected consistently | Original order, refund or cancellation record, processor entry, and return reconciliation |
| Claimed exempt sale | Whether the transaction’s tax treatment is supported by the required documentation | Invoice, exemption documentation, and relevant customer or transaction records |
| Business purchase | Whether sales tax was paid to the vendor or use tax was reported where applicable | Vendor invoice, proof of tax paid, purchase ledger, and use-tax return entry |
Frequently asked questions
What happens during an Indiana sales tax audit?
The Indiana Department of Revenue reviews records to determine whether your business correctly handled Indiana sales and use tax. It may compare returns with sales reports and transaction records, examine exemption support, and review purchases for tax paid or use tax reported. If it proposes additional tax, it may issue an audit summary and Notice of Proposed Assessment.
How far back can Indiana audit sales tax returns?
The period depends on the applicable assessment time limit, filing history, and whether a written extension applies. DOR’s audit manual directs auditors to identify open periods and recognizes written agreements extending the assessment period. Check the periods in your notice and ask DOR to explain the basis for them rather than assuming a fixed lookback applies.
How long do I have to protest an Indiana sales tax assessment?
You generally have 60 days from the date printed on the proposed assessment to file a written protest with the Indiana Department of Revenue. DOR states that this statutory deadline cannot be extended. Follow the current instructions on the notice and DOR appeals page, and keep proof that you filed on time.
How do I appeal an Indiana Department of Revenue audit?
To challenge a proposed assessment, submit a written protest explaining your reasons, the Protest Submission Form, and supporting records within the 60-day deadline. DOR accepts protests through INTIME and by mail under its current instructions. You may request an administrative hearing; if you disagree with DOR’s resulting decision, further review may be available in the Indiana Tax Court, subject to applicable deadlines and procedures.
Can I challenge an Indiana sales tax audit assessment?
Yes. You can protest a proposed assessment by explaining which findings or calculations you dispute and providing evidence that supports your position. File within 60 days of the date printed on the assessment; the deadline is statutory and cannot be extended.
What records should I provide for a sales tax audit?
Provide the records requested in the notice, which may include filed returns, transaction-level sales data, invoices, marketplace and payment reports, refund records, shipping information, exemption documentation, accounting reconciliations, and purchase invoices. Include evidence of sales tax paid or use tax reported on business purchases. Organize the files and explain any missing records or differences between reports.
Can a tax attorney represent my business during an Indiana sales tax audit?
A tax attorney can represent your business in an audit and related proceedings. Discuss the scope of representation directly with the attorney, especially if the matter may proceed to a formal protest or court appeal. You can also use a hands-on compliance service for record organization and audit-response support.
What happens if I ignore an Indiana sales tax audit notice?
Ignoring a notice can leave DOR without your records or explanation and may lead to an assessment based on the information available to the department. If you then fail to pay or protest a proposed assessment within the required period, DOR says it may demand payment and you may lose the right to protest that assessment. Contact the auditor promptly and follow the deadlines in the notice.
How we handle this for you
The mechanics in Indiana are manageable on their own; the cost is the time it takes every single filing period, in every state you are registered in. We are a managed service: our team registers you with the Indiana Department of Revenue, prepares and files your returns, and keeps you compliant period after period. You get one point of contact and one invoice — you do not get another dashboard to learn.
See our sales tax compliance services, check where you have obligations with the nexus calculator, or talk to us about Indiana.
Official sources
- https://www.in.gov/dor/resources/legal/appeals/
- https://www.in.gov/dor/files/dor-protest-guide.pdf
- https://www.in.gov/dor/files/audit-manual.pdf
- https://www.in.gov/dor/i-am-a/tax-professional/the-collection-process/
- https://www.in.gov/dor/i-am-a/business-corp/business-faq/
- https://www.in.gov/dor/i-am-a/business-corp/sales-tax/
Reviewed by Paul le Roux, CA(SA). Sales Tax Compliance USA handles US sales tax registration, filing and remittance for cross-border and domestic ecommerce sellers as a fully managed service.
This page is general information for educational purposes and does not constitute legal or tax advice. Sales tax rules change and depend on your specific facts. Consult a qualified tax professional about your own position.
Related guides
Other Indiana guides: Amazon FBA · Back sales tax · Filing · Foreign sellers · Marketplace facilitator · Permit
Audit defence in nearby states: Illinois · Ohio
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