Key tax dates and to-do-list: August 2026

August may be one of those months that seems like it should be quiet, but it’s also one of those. months that sits between the spring filing season and fall extension deadlines, September 15 for extended S-corp and partnership returns, and October 15 for extended individual and C-corp returns.

That means flagging which clients still owe documents, the returns are complex enough to need extra review time, and ensuring you are prepared before the crunch hits in terms of capacity. August is also a good time for staff training, workflow cleanup, technology or software renewals, and any process improvements you’ve been putting off since April.

With your clients, August conversations should be forward-looking rather than deadline-driven. For example, this is the time for a mid-year tax planning where you review income projections, discuss entity structure or elections that need to be locked in before year-end, and flag Q3 estimated payments due September 15. For business clients on extension, it’s worth checking in now on bookkeeping gaps, K-1 dependencies, or shareholder basis questions that could stall the September 15 filing. And, for any client with a benefit plan or nonprofit filing obligation, a quick confirmation that their August deadlines are handled—whether by your firm or elsewhere—would be good for your clients.

Along the way, be sure to pay attention to these important IRS and compliance deadlines.

In August, it is recommended that you:

• Review S-corp and partnership extended returns. Begin preparing extended returns for the September 15 deadline. Confirm all client data has been received.
• Audit your own pricing. Pull your top 20 client engagements and compare what you charged to what you delivered. Which engagements are most underpriced? That list becomes your value-based pricing pilot group.
• Identify three clients for a pricing conversation. Choose three clients whose engagements have grown in complexity without a corresponding fee adjustment. Plan to have the pricing conversation before year-end.
• ​​Draft or update your service tier structure. Before you can price by scope, you need to define what each tier includes. Use August, while the season is quieter, to write down what your three levels of engagement actually look like in practice.

Key Compliance Dates

Monday, August 10: Tips reporting for July (Form 4070). Extended due date for Form 941 Q2 if all deposits were made on time.

Wednesday, August 12: Communications and air transportation taxes deposit for the first 15 days of July.

Friday, August 14: Regular-method excise taxes deposit for the last 16 days of July.

Monday, August 17: Monthly payroll tax deposit for July (Form 941).

Wednesday, August 26: Communications and air transportation taxes deposit for the last 16 days of July.

Friday, August 28: Regular-method excise taxes deposit for the first 15 days of August.

Intuit® Accountant Resources

• Key Tax Facts for 2026 and Key Tax Facts for 2025
• The August 2026 calendar with filing deadlines and reminders for you and your clients.
• Tax update for TY26: Navigating the OB3 Act and more
• One Big Beautiful Bill summary and tax changes
• Navigating the tax landscape
• IRS annual inflation adjustments for tax years 2025 and 2026