Louisiana Sales Tax Penalty and Interest Calculator

How Louisiana Sales Tax Penalties and Interest Work

Sales tax in Louisiana is administered by the Louisiana Department of Revenue (LDR). For most taxes, including sales and use tax, the LDR charges a penalty of 5 percent of the tax due for each 30-day period — or fraction thereof — that the failure to file or pay continues, up to a maximum of 25 percent. The interest rate is set at three percentage points above the judicial interest rate, reviewed annually each January 1 under La. R.S. 47:1601.

The interest rate ran at 11.75% for 2024, then 11.25% for 2025, and dropped to 10.5% per year starting January 1, 2026. Because penalties apply per filing period and increase every 30 days, a business with delinquent returns across several periods can build a tax liability far larger than the original tax due, which is exactly what this multi-period calculator totals.

Late Filing vs. Late Payment Penalties in Louisiana

Louisiana treats late filing and late payment as separate penalty events. A late filing penalty accrues at 5 percent of the tax due for each 30-day period (or fraction thereof) the return remains unfiled, up to a maximum of 25 percent. A separate late payment penalty accrues on the same schedule for the unpaid tax balance. Because these are calculated independently, both can run simultaneously — meaning the total amount due can grow faster than many business owners expect. There is no dollar minimum. (La. R.S. 47:1602)

Example: If your business owed $25,000 in Louisiana sales tax for a period and resolved it many months late, penalties plus accrued interest can add thousands on top of the original tax due — and that is for a single period.

Both the date you file and the date you pay matter. A tax return filed six months late is treated differently from a return filed on time, where only the payment was late.

How Louisiana Interest Applies

Louisiana charges an interest rate set at three percentage points above the judicial interest rate, reviewed annually each January 1 under La. R.S. 47:1601. The current interest rate for all of 2026 is 10.5% per year — approximately 0.875% per month, or 0.028767% per day. Interest accrues daily on the unpaid tax amount, beginning the day after the due date and continuing until the full balance is paid, regardless of whether a payment plan is in place.

The Louisiana Department of Revenue website publishes historical and current interest rates on Form R-1111. For audit assessments, interest reaches back to the date the tax originally should have been paid — not the date the LDR issued the bill. Sales taxes are due and payable to the LDR on or before the 20th day of the month following the reporting period.

Why Sales Tax Debt Is Different From Income Tax Debt

This is the part most business owners underestimate. When you collect Louisiana sales tax from a customer, you are holding money that belongs to the state. If that money is not remitted, the LDR may treat it as a trust-fund tax, not an ordinary tax obligation you simply fell behind on.

That distinction changes what the state can do:

• Collected-but-unremitted tax is viewed as the state's money, not yours.
• Responsible-person liability can reach owners, officers, partners, members, or employees who controlled the money.
• Personal assessments may survive even if the business closes or files for bankruptcy.
• Business bank levies, liens, and license suspension can move faster than with income tax debt.
• Audit escalation and, in serious cases, criminal referral can occur where tax was collected and intentionally not paid.

Not every case is criminal — most are not. But serious cases, especially where tax was collected and knowingly kept, can involve criminal exposure. That is why delinquent sales tax debt deserves a careful look early.

Louisiana Sales Tax Agency and Enforcement

Louisiana's sales and use tax is administered by the Louisiana Department of Revenue. The LDR has broad authority to pursue collection of unpaid taxes through notices, assessments, levies on business bank accounts, liens, and permit actions. Notices typically arrive by mail and can range from a balance-due bill to a delinquency notice, an audit notice, a lien filing, a levy on business bank accounts, or a threat to the sales tax permit or business license.

State revenue agencies generally have strong tax collection tools and may pursue responsible persons for trust-fund amounts. Payment plans, penalty waiver, and settlement options may exist, but availability depends on the facts and the LDR's rules. If you have received any notice from the LDR, it is best reviewed promptly — sales tax timelines move faster than most business owners expect.

Louisiana Sales Tax Audit Assessments

If your balance comes from an LDR audit assessment, the numbers above may not match the state's figures. LDR audits can add tax, penalties, and interest, and findings often involve underreported sales, denied exemption or resale certificate transactions, missing exemption certificates, online sales, or cash-sales reconstructions. A notice of assessment issued after an audit includes the amount of tax due and explains your appeal rights, including the right to petition the Louisiana Board of Tax Appeals.

Audit assessments also carry appeal and protest deadlines that can be short. Ignoring an audit notice usually makes the outcome worse. If you received an LDR assessment, the most useful next step is a review before the deadline passes — not a recalculation.

Responsible-Person / Personal Liability

In Louisiana, owners, officers, partners, members, or other responsible persons may be held personally liable for unpaid sales tax under certain circumstances — particularly trust-fund tax that was collected from Louisiana customers but never remitted to the state.

• Closing the business does not always eliminate the tax obligation or personal exposure.
• LLC or corporate protection may not fully shield against a trust-tax assessment.
• Who signed returns, controlled the bank accounts, decided which bills got paid, or handled the tax money can all matter.
• Rules vary by facts, and personal liability depends on the circumstances.

Because a personal assessment can attach to your own assets, this is worth reviewing early — before the LDR names a responsible person. (La. R.S. 47:1561.1)

Business Closed With Unpaid Louisiana Sales Tax?

A closed business does not automatically erase unpaid sales tax obligations. The LDR can still pursue the entity and, where trust-fund tax was collected, may pursue the responsible people behind it. Final tax returns, unfiled periods, and a past-due balance are common triggers for tax collection action and personal assessment. If your business has delinquent taxes in Louisiana still owed, it is better to understand the exposure than to wait for a notice.

Louisiana Penalty Relief, Waiver, and Resolution Options

Depending on the facts, options may include penalty abatement or waiver, a reasonable-cause request, a payment plan, voluntary disclosure for unregistered or unfiled periods, amended tax reports, a petition to the Louisiana Board of Tax Appeals, a settlement or offer where the state allows it, a business-hardship request, a responsible-person defense or review, and tax compliance cleanup for missing returns.

Penalty relief is not automatic. Under La. R.S. 47:1603, the LDR will generally consider facts such as your filing history, payment history, the reason for noncompliance, whether tax was collected, whether the business cooperated, and whether you are now compliant. To request relief, taxpayers submit Form R-20128 (Request for Waiver of Penalties for Delinquency) electronically through LaTAP or by paper. Before a waiver can be considered, all returns must be current, and all non-waived taxes, fees, and interest must be paid. See LAC 61:III.2101 for complete waiver guidelines.

Louisiana Sales Tax Payment Plans

Louisiana allows installment agreements for unpaid sales tax through the Louisiana Taxpayer Access Point (LaTAP) online system. A payment plan may slow some collection actions, but terms and eligibility depend on the balance, the periods involved, whether returns are filed, and your compliance history.

Payment plans require a $105 setup fee, have no stated minimum term for businesses, and a down payment is encouraged but not required for business accounts. Getting the plan structured correctly the first time is important — especially if keeping the business open or staying compliant with new filing deadlines matters.

When to get help immediately

Do not rely only on an online calculator if any of these apply to your Louisiana sales tax situation:

• Tax was collected from customers but not remitted to the LDR.
• The state issued a levy notice and filed or threatened a lien.
• The state threatened to suspend your sales tax permit or business license.
• The business is under audit, or the LDR is asking about responsible persons.
• The business closed with unpaid sales tax still owed.
• Sales tax money was used for payroll, rent, vendors, or other business expenses.
• You have received multiple notices, or there is a court date, subpoena, or investigator contact.
  

Common Louisiana Sales Tax Cases We Review

If any of these sound like your situation, a confidential review is worth more than a recalculation:

• A restaurant or retailer collected Louisiana's sales tax but used the funds for payroll, rent, or vendors.
• A contractor, shop, or seller missed multiple filing periods and failed to file a timely return.
• The business closed with unpaid Louisiana sales tax still owed.
• The LDR issued a sales tax audit assessment.
• An owner or officer received a personal-liability / responsible-person questionnaire.
• The sales tax permit or business license was threatened or held.
• A bank levy or lien was filed against the business.