Most couples don’t think about taxes between April and December. That’s exactly when you should — and not because tax planning is fun, but because mid-year is when you have something nobody has in April: time to fix things before they become expensive.
Here’s a focused 30-minute checklist worth doing in May or early June, with the Q2 estimated payment deadline (June 15) as your forcing function.
1. Are you on track for the right amount of withholding?
The most common preventable tax surprise for couples filing jointly is under-withholding from two W-2 paychecks. The IRS withholding tables assume each W-4 represents the entire household income — so when both spouses checked “Married filing jointly” with nothing else, the standard deduction effectively gets applied twice and the household ends up short by $2,000–$8,000 at filing time.
Five months into the year is when you can still spread an additional withholding amount across the remaining paychecks without it being painful. Five months from year-end (November) is much harder — you have to load the same shortfall into roughly half the paychecks.
Quick check: project both spouses’ annualized wages (year-to-date × 12 / current month). Run them through the two-earner W-4 calculator. If it shows a meaningful per-paycheck extra-withholding amount, submit an updated W-4 to the higher earner’s payroll team this week.
2. Did your wages change since you last set your W-4?
Most couples set their W-4 once and forget. But common mid-year events change the math:
- Promotion or raise (5%+) — pushes total household income into a higher bracket; default withholding falls further behind
- Job change with a sign-on bonus — bonuses are withheld at a flat 22% (or 37% above $1M), which often differs from your actual marginal rate
- Spouse stops or starts working — completely changes the two-earner shortfall calculation
- Side gig / 1099 income — withholding doesn’t cover it at all (see section 4)
If any of these happened in the first half of the year and you haven’t updated your W-4, do it now. The dollar adjustment to extra withholding is typically smaller than people expect.
3. Estimate your full-year tax — even with the rough numbers you have now
By mid-May you have 4-5 months of pay stubs, some clarity on bonuses, and a sense of any side income. That’s enough to run a credible projection through the Combined Income Tax Estimator.
What you’re checking for:
- Total estimated tax vs. YTD withholding × annualization factor. If withholding-on-pace is meaningfully below estimated tax, you have a brewing shortfall.
- Effective vs. marginal rate. If your marginal is 24% and your effective is 11%, you have room to convert traditional IRA → Roth at the 24% rate before year-end without bumping into a higher bracket. (More on this in section 6.)
- Refund or balance due. A small refund or small balance due is the goal. A $5,000+ refund means you’re lending the government interest-free; a $5,000+ balance due triggers underpayment penalties next April.
This projection takes 10 minutes if your situation is straightforward. Worth doing.
4. If you have any 1099 income, your Q2 estimated payment is due June 15
If either spouse has gig work, freelance income, rental income, investment income that isn’t being withheld, or business income — quarterly estimated taxes apply, and Q2 is due June 15, 2026 (not the usual 15th — that’s only the case for Q1 and Q3; Q2 is mid-June because the IRS made the quarters uneven for reasons no one can fully explain).
The “safe harbor” rules let you avoid underpayment penalties if you pay either:
- 90% of your current year’s actual tax liability, or
- 100% of last year’s tax liability (110% if last year’s AGI exceeded $150,000)
For most couples with predictable income, the simplest strategy is to base quarterly payments on 110% (or 100%) of last year’s total tax divided by 4. That gets you safely into the harbor regardless of how this year actually shakes out.
If you missed the Q1 deadline (April 15) — and a lot of people do, especially if Q1 income was a surprise — pay the catch-up amount now along with Q2. Penalties accrue daily, so closing the gap mid-year costs less than waiting.
If you’re a 1099 contractor in New Mexico (or any gross-receipts state), don’t forget GRT is separate from your federal estimated payments. Same quarterly cadence, different forms.
5. Are you maxing out tax-advantaged accounts?
May/June is the right time to check whether you’re on track for the year’s contribution limits:
- 401(k): $23,500 employee limit for 2026, with $7,500 catch-up if 50+. Check your YTD on a pay stub and project to year-end. If you’re way under, ask payroll to increase the deferral percentage now — the math works out smoother than scrambling in November.
- HSA: $8,550 family limit for 2026. If you have a high-deductible health plan, this is the best tax-advantaged dollar in the code (deductible going in, tax-free growth, tax-free out for medical). Most couples leave room on the table.
- Traditional or Roth IRA: $7,000 each ($8,000 if 50+) for 2026. You have until April 15, 2027 to contribute, but earlier is better for the compounding.
- Dependent Care FSA: $5,000 limit (combined) for the whole household. If you have eligible expenses, get this set up — you can’t enroll mid-year typically, but you can plan for next year’s open enrollment.
For pre-tax 401(k) and HSA contributions, increasing the deferral now lowers your AGI for the rest of the year, which can have downstream effects on credits and phaseouts.
6. Roth conversion sweet spot
If one spouse is between jobs, or in a low-income year (sabbatical, post-layoff, parental leave), or you have a year with unusually low bonuses — that’s the year to consider converting traditional IRA balances to Roth.
The conversion is taxed at your current marginal rate. In a low-income year, that rate might be 12% or 22% when your “normal” rate is 24%, 32%, or higher. Convert enough to fill up the lower brackets without spilling into the next one, and you’ve moved future tax-free growth to a Roth at a discount.
Use the Combined Income Tax Estimator to test conversion amounts: enter your projected income with the proposed conversion added to “other ordinary income,” see how it changes your marginal rate, find the amount that maxes out your current bracket without going over.
This is one of the highest-value planning moves for couples and one of the easiest to miss because it’s not automatic.
7. Life changes that need a W-4 update
The W-4 should be updated whenever your tax picture changes, not just when you change jobs. Mid-year is a good time to ask:
- Did we get married this year? (Switch to MFJ on both W-4s.)
- Did we have a child? (Add to Step 3 for the CTC.)
- Did a child turn 17? (Remove from Step 3 — CTC ends the year they turn 17.)
- Did one of us start school, take an unpaid leave, or significantly reduce hours? (Recalculate the two-earner shortfall.)
- Did we buy or sell a home? (Property tax + mortgage interest may push you over the itemized threshold — fewer credits/deductions need to come from withholding.)
- Did either of us start receiving Social Security or pension income? (Different withholding rules apply.)
Each of these can shift your withholding requirement by $1,000+ annually. Catching them now is much better than catching them in April.
8. Things you can defer to year-end
Not everything needs to happen in May. The following move more efficiently in October-December:
- Charitable contributions (donor-advised fund bunching, year-end giving for next year’s deduction)
- Tax-loss harvesting in taxable brokerage accounts (only relevant if positions are actually down by then)
- Roth conversion final amount (you have better income visibility by November)
- Itemized vs standard decision (don’t lock in until you have Q4 numbers)
Note these on your calendar for November but don’t sweat them now.
The 30-minute version
If you only have time for one thing this week, it’s this:
- Open last paystub for each spouse, multiply YTD federal wages × (12 / current month) to project annual wages.
- Run those into the W-4 calculator.
- If it recommends extra withholding, submit a new W-4 to the higher earner’s HR team.
That single 5-minute task captures roughly 80% of the value of a full mid-year review for most dual-W-2 couples. The other items above matter more for higher-complexity situations.
Bottom line
The April-to-December tax silence is when problems quietly compound. Mid-May is when fixing them is still cheap. Pick one thing from this checklist — the withholding update is almost always the right one — and do it before Memorial Day. April-you will be grateful.