Hello! Each of you should complete Steps 1 of the W4 and check the Married Filing Jointly box. The person with the highest paying job, your wife in this case, should complete Steps 2-4. Since you each only have one job, your wife should check the box in Step 2c and then proceed to Steps 3-4.
Since we are halfway through the year, I recommend using this tax calculator to estimate how much you may owe and then comparing that to your withholdings after you adjust your W4. If it looks like you may owe, you can make an additional payment directly to the IRS or divide that amount by the number of pay periods and include that in one or both your W4s in Step 4c.
Thank you for reaching out!
Michael, CPA
