The late filing (
failure to file) penalty kicks in if you miss the tax filing deadline 2024, while the underpayment penalty (
failure to pay) is for not paying enough taxes throughout the year. Filing late usually results in a 5% monthly penalty on unpaid taxes, up to 25%, while underpayment penalties are more like a gradual interest charge—around 0.5% of the unpaid amount per month.
Say you’re a freelancer who didn’t make estimated quarterly payments last year, thinking you’d pay it all at tax time. The IRS will likely charge an underpayment penalty, calculated based on how much you should’ve paid each quarter.
Then, if you don’t file by April 15, they’ll also add a late filing penalty. Both can add up, so if you’re self-employed, paying quarterly estimated taxes and filing on time can help you avoid the double hit.
The way your tax penalty grows and changes depends on how late your return and payment are. For each month (or part of a month) that your tax return is late, the total combined penalty can reach up to 5% of the unpaid tax—4.5% for filing late and 0.5% for paying late. This can add up, but it maxes out at 25% of what you owe when you finally file.
The late filing penalty is based on the tax that’s still unpaid after the April due date. So, unpaid tax means what’s left after taking into account anything you’ve already paid through withholding, estimated payments, or any credits.
Now, let’s say five months go by, and your tax bill is still unpaid. The failure-to-file penalty maxes out at that point, but the failure-to-pay penalty keeps running until you’ve paid in full or until it also reaches 25%. When both the late filing and late payment penalties apply at the same time, the combined maximum penalty usually tops out at 47.5% of the unpaid tax.
If you’re over 60 days late, there’s a minimum penalty for not filing. For 2024, this minimum penalty is either $485 or 100% of the unpaid tax, whichever is less. So even if you’re only a little late, it’s still a good idea to file as soon as possible to avoid these extra charges adding up.
To manage underpayments, you should consider adjusting your withholding (talk to your employer about it) or making estimated payments throughout the year. You can use FlyFin’s
estimated tax calculator to total your dues.