Q3 federal estimates are due Tuesday, September 15, 2026. This is the quarter that nails people because Q2 was only two months.
This is a checklist, not tax advice. It will not tell you what you owe. It is not a penalty guarantee. If income jumped, you have an S-corp, or you are multi-state, talk to a CPA before you pay. Not affiliated with the IRS.
Do this the week before Sep 15
- List what actually hit your account Jun 1–Aug 31. Client payments only. Ignore "they said they'd pay."
- Subtract expenses you can document (software, contractors, ads, a real home-office % if you already use one). If you don't have the receipt, don't invent it.
- Move a set-aside out of checking. A common starting point for 1099s is 25–35% of net. Yours may be different. If the money stays in checking, you will spend it.
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Pay the IRS via Direct Pay or EFTPS. Screenshot the confirmation. Put it in a folder named
taxes-2026. - Check your state. NY, CA, and others often want their own estimate. This post does not calculate that.
The cash-basis trap
A 1099 invoice log has to be cash-basis or your quarterly estimate is a lie: March invoice, April payment = Q2 income. Key the quarter off payment date, not invoice date.
If you already paid 100% of last year's total tax (Form 1040 Line 24) split across four dates, you may be in safe harbor even if 2026 is bigger (110% if AGI was over $150k). If this is year one off W-2, ignore last year and park a set-aside the day each deposit clears.
If this still lives in 14 Google Docs
That's the whole problem. Pipeline, invoices, and this quarterly worksheet belong in one place you open every week — not the night before a due date.
I packed that into a $29 Freelance Ops Pack (Sheets OS + invoice PDF + the quarterly worksheet): https://yeraldinmueses.gumroad.com/l/letldi
Comment RITUAL if you want the checklist as a standalone one-pager and I'll send it.
