Every year, we talk to dentists who are so focused on getting their return filed that they miss an equally important question:
Did you fully fund your retirement plan for last year?
For practice owners, the tax filing deadline and retirement contribution deadlines are directly linked, and in some cases, filing an extension doesn't only buy you more time with the IRS, it buys you more time to save.
Here's what matters most heading into April and to know for the 2026 tax year:
401k(k) Profit Sharing
While salary deferrals from W2 income had to be funded by 12/31/25, you have until your tax filing deadline, including extensions, to make profit sharing contributions for the prior year. That means if you file an extension, your 401(k) Profit Sharing contribution deadline for tax year 2025 moves all the way to October 15, 2026. But don't file your taxes until you've funded your Profit Sharing.
This ability to create 2025 tax deductions with a "retroactive" Profit Sharing contribution is a very useful tax tool.
For Associates:
SEP IRA - the most flexible deadline
If you are a 1099 dentist or have speaking or consulting work, you may be maximizing retirement savings through a SEP IRA. You have until your tax filing deadline, including extensions, to make contributions for the prior year. That means if you file an extension, your SEP IRA contribution deadline for tax year 2025 moves all the way to October 15, 2026. For 2025, the maximum SEP IRA contribution is $70,000*, the calculations comes to around 20% of compensation. For sole-proprietor dentists or those with other types of Schedule C income, that's a meaningful tax savings worth taking the time to calculate.
Depending on how your entity files (S-Corp, schedule C), your calculation may be on W2 income or net business earnings; include your tax or financial advisor when finding your number.
Solo 401(k): the window is partially open
Solo 401(k) plans have a split deadline, and this is where it gets important. The employee deferral portion (the salary reduction contribution you make as an employee) had to be elected and funded by December 31st of the tax year.
The employer profit-sharing contribution, however, follows the same flexible rule as the 401(k): you can fund it up to your tax filing deadline, including any extension. For 2025, total combined contributions (employee + employer) to a Solo 401(k) are capped at $70,000*.
*If you're over 50, you're entitled to catch up contributions. Between 60 and 63? It's even better!
For those 50 or over, there's an extra catch-up contribution of $7500 (2025) or $8000 (2026) that adds to the maximum salary deferral, and ultimately the maximum allowable of employer+employee contributions in the plan.
SECURE 2.0 introduced a higher "super catch-up" contribution limit for people aged 60 through 63.
For 2025, the super catch-up meant an additional $11,250 on top of the standard limit compared to $7,500 for everyone else over 50.
If you're in that age window, make sure your payroll set up, plan documents and contributions reflect that higher allowance. Not all plan administrators have updated their systems automatically.
The bottom line before you file
Before you or your CPA hits submit on your return this year and future years, it's worth asking three questions:
1. Did I contribute the maximum I'm allowed to for last year?
2. If I didn't, is there still time (and cash available)?
3. Would filing an extension create any useful flexibility or tax deduction opportunities?
For many dentists, the answers could mean thousands of additional dollars going into a tax-advantaged account instead of to the IRS.
These decisions are specific to your practice structure, income, and plan type. If you want to walk through what makes sense for your situation, we'd love to set up a time to talk.
Disclaimer - IRS CIRCULAR 230 DISCLOSURE
In compliance with requirements imposed by the IRS pursuant to IRS Circular 230, we inform you that any U.S. tax advice above is for informational purposes not intended or written to be used, and cannot be used, for the purpose of (i) avoiding penalties under the Internal Revenue Code or (ii) promoting, marketing or recommending to another party any transaction or matter addressed herein.