Tax Planning · Jacksonville, FL
Missed a Quarterly Estimated Tax Payment? Here's What It Actually Costs You
By Remi Matteo · Matteo Bookkeeping · Jacksonville, FL
TL;DR
- The 2026 quarterly deadlines are April 15, June 15, September 15, and January 15, 2027.
- The penalty accrues from the missed date forward, roughly 8% a year, and keeps growing until you pay.
- Paying late is much cheaper than not paying at all. Pay what you can now.
If you are self-employed, a sole proprietor, or taking distributions from an S-Corp, the IRS expects estimated tax payments four times a year, not just one lump sum in April. Miss one, and the notice usually is not immediate. The penalty just quietly starts accruing, and most people do not find out until they file the following year and see a number they were not expecting.
The 2026 deadlines, so there is no confusion
Quarterly payments for 2026 are due April 15, June 15, and September 15, with the final payment due January 15, 2027. These dates apply to sole proprietors, partners, and S-Corp shareholders who expect to owe $1,000 or more for the year.
What actually happens if you miss one
The underpayment penalty accrues daily from the date the payment was due, at an annual rate of roughly 8%. It is not a flat fee. It grows every day the balance sits unpaid, and it does not get wiped out just because you eventually file and pay in April. The longer it sits, the more it costs, which is why the fix is almost always to pay something now rather than wait for the next deadline.
What to actually do about it
Pay the missed amount as soon as you can
Even a partial payment stops the penalty from growing on that portion. Do not wait for the next quarter to "catch up all at once."
Check if you qualify for safe harbor
If you paid at least 100% of last year's tax bill through the year (110% if your income was higher), you may avoid the penalty entirely even if this year's number is bigger. This only works if you know last year's numbers accurately.
Ask about first-time penalty abatement
If you have filed and paid on time for the prior three years, the IRS will often waive the penalty once, just for asking. It is not automatic. You have to request it.
Fix the number for next quarter
A missed payment is usually a symptom of not knowing what you actually made that quarter. Current, accurate books are what make the next estimate correct instead of a guess.
Why this keeps happening to the same business owners
Estimated payments are supposed to be based on what you actually earned that quarter. If your books are a month or two behind, you are estimating a number without real data behind it, and that is how quarters get missed or badly underpaid. Our 2026 tax planning checklist covers this and several other year-end blind spots. If you got here because a notice already arrived about it, see our post on what to do when you get an IRS notice.
Not sure what you actually owe or when the next payment is due?
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Book My Free Financial Health CheckQuick Questions
Do I have to pay the missed quarter all at once?
No. Pay the missed amount as soon as you can to stop the penalty from growing, then keep making the remaining quarterly payments on schedule. There is no requirement to pay everything at once.
Can the penalty be waived?
Sometimes. The IRS offers a first-time penalty abatement if you have filed and paid on time for the prior three years, and will also consider waivers for reasonable cause like a disaster or serious illness. It is worth asking rather than assuming you owe it.