Personal Finance Hack: Treat December 15 Like the Q4 Tax Deadline. Here’s Why.
If you’re a law firm partner or self-employed professional, you’re probably familiar with quarterly estimated taxes — and how frustrating they can be to time right.
But here’s a personal finance hack we have for our clients: Although the Q4 estimated tax payment for the IRS isn’t due until January 15 we at Hark Financial Planning often advise clients to treat December 15 like the true deadline.
Here’s why this small shift in timing can have a big payoff for your tax bill and your peace of mind.
1. Your Tax Year Ends December 31
Even though the final estimated tax payment for Q4 is technically due in mid-January, your income and deductions for the year end on December 31. That means any action you take after that date, such as donating to charity, harvesting losses, or adjusting business income won’t affect your current year’s taxes.
So if you’re waiting until January 15 to think about your final payment, you’re flying blind. By mid-January, it’s already too late to change your outcome. The only move left is to pay the bill, not reduce it.
When you treat December 15 like your final deadline, you give yourself the gift of time and more flexibility to improve your position.
2. You Can Lock In Deductions Now
Some clients choose to make property tax payments before December 31, even though it’s not technically due yet. This is because if you’re itemizing deductions, state and local tax (SALT) payments are deductible in the year you make them.
That means prepaying your property taxes can reduce your federal tax bill this year, not next. Of course, there are nuances (like the SALT cap), but for many high earners, the benefit is real.
You can also consider making your January mortgage payment in December to move the interest deduction into 2025. These can be especially powerful if you are on the borderline of itemizing deductions, since this may push you over the limit. Another strategy is to consider pairing this with charitable gift bunching. It’s worth reviewing your projection to see if early payment could help.
3. Avoid Surprises and Penalties
If you’ve had an especially strong Q4 with things like a big bonus, a spike in income, or better-than-expected business revenue, your previously calculated estimated payments may now fall short.
Rather than get surprised with a big bill (or penalty) in April, treating December as your final review period gives you time to assess:
Do you need to increase your Q4 payment?
Should you accelerate deductions before year-end?
Is there still time to shift income into next year?
Your future self will thank you for asking those questions now, not when you’re filing your return.
4. Make the Holidays Simpler
Let’s be honest: Nobody wants to do tax planning the first week of January.
You’re recovering from the holidays. You’re trying to get back to work. And the IRS isn’t exactly at the top of your to-do list. That’s another reason why we encourage clients to wrap up year-end planning by December 15. Think of it as your personal financial finish line. Once you’ve crossed it, you can enjoy the holidays knowing your finances are in good shape.
Don’t Wait Until the IRS Tells You It’s Due
The January 15 deadline is real, but it’s not as strategic as setting a December 15th deadline for yourself. If you want to use your Q4 payment to your advantage, the time to act is before the end of the year.
A simple tax projection can show you whether you’re on track or whether a few adjustments could save you money. Need help running the numbers or deciding when to pay? We’re happy to help.
