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What penalties apply for unfiled or late tax returns?

The IRS imposes two separate penalties for late returns: failure to file and failure to pay. Understanding both matters because they can apply simultaneously.

The failure to file penalty runs 5% of unpaid taxes for each month your return is late, maxing out at 25%. This is the bigger penalty by far, which is why filing on time matters even when you can’t pay what you owe.

The failure to pay penalty is 0.5% per month of the unpaid balance, also capped at 25%. When both penalties apply in the same month, the failure to file penalty drops to 4.5% so the combined monthly hit stays at 5%. Interest accrues on top of everything at rates that have been running around 7-8% annually in recent years.

Returns filed more than 60 days late trigger a minimum penalty. It’s the lesser of $510 (for 2024) or 100% of the tax owed. Someone who owes $400 and files three months late faces a penalty equal to their entire tax bill.

Business returns work differently. S-corporations and partnerships face per-shareholder or per-partner penalties for late filing regardless of whether any tax is due. A four-person S-corp that files three months late could owe over $3,000 in penalties even if the return shows zero tax liability. The IRS takes business filing deadlines seriously.

Idaho adds its own penalties on top of federal ones. The state charges 2% per month for late filing up to 25%, plus 0.5% monthly for late payment. If you’re behind on federal, you’re probably behind on state too. The combined penalties grow quickly.

The practical takeaway: always file on time, even without full payment. The filing penalty is ten times the payment penalty. You can set up a payment plan after filing, but you can’t undo the penalty for not filing. IRS audit representation can help negotiate penalty abatement if you have reasonable cause for being late, but prevention is far simpler than remediation.

Nampa bookkeepers and tax professionals see this pattern regularly. Someone falls behind one year, avoids dealing with it, and by the time they reach out, they’re facing thousands in compounded penalties. The sooner unfiled returns get addressed, the less painful the fix.

The Treasure Valley's Tax and Accounting Team

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