If you made money this year from a side hustle, a freelance gig, a rental property, or even a decent chunk of stock dividends, the IRS expects you to pay taxes on it as you go—not just in April.
The next estimated tax deadline is September 15.
Miss it and the penalty clock keeps ticking, even if you plan to pay everything you owe when you file next spring.
Here's the part that trips people up: if you're a regular W-2 employee, your employer withholds taxes from every paycheck.
So the IRS runs a "pay-as-you-go" system, and it's on you to send in quarterly payments covering what you'll owe.
You generally need to make estimated payments if you expect to owe at least $1,000 in taxes for the year after subtracting withholding and credits.
That threshold snags more people than you'd think—one weekend gig, a cash tutoring side job, or a sold investment can push you over it.
Each quarter has its own deadline: April 15, June 15, September 15, and January 15 of the following year.
Fall behind on one and you're not just late on that chunk—you're accruing interest and a penalty on the amount you should have paid.
The penalty itself works out to roughly 0.5% of the unpaid amount per month, up to 25%, plus interest that adjusts with the federal rate.
On a $5,000 shortfall, that can quietly add a few hundred dollars to your bill.
Not catastrophic, but entirely avoidable.
If you pay in at least 90% of what you owe for the current year, or 100% of what you owed last year (110% if your income was high), the IRS generally won't hit you with the underpayment penalty—even if you still owe a balance in April.
If your income is uneven, you can also use the "annualized income installment method" to base each payment on what you earned that specific quarter.
It's more paperwork, but it can shrink or erase a penalty if most of your money came in late in the year.
Don't panic-pay a lump sum you can't afford.
You can catch up at any time using IRS Direct Pay or your IRS online account, and adjusting your W-2 withholding for the rest of the year can cover the shortfall without a separate check.
One more thing worth checking: if you collected unemployment or received a big one-time payment, you may qualify for a waiver of part of the penalty if the underpayment was due to an unusual event.
My take: estimated taxes feel like a chore until the first penalty notice shows up, and then they feel like a fire drill.
If you made extra money this year, log into your IRS account today and run the numbers.
Final Thoughts
Ten minutes now beats a surprise bill and a penalty later.