Splitting standard deduction

Yes, that is correct.

Each employer only knows what they pay to you. So, unless you tell them otherwise, your employer is going to assume that your income from them is your only income, that you will take the full standard deduction, and that there are no adjustments to income or dependents.

If you have two jobs -- whether you individually or each spouse on a return has a job -- then every employer is going to make the same assumptions. This means that, overall, you will be under-withheld because both employers reduce your taxable wages by the full standard deduction.

An example -- assume that you are single, no dependents, no adjustments to income, and you take the standard deduction:

• Job 1 pays you gross wages of $40,000
• Job 2 pays you gross wages of $60,000
• Total (gross) income is $100,000
• Taxable income should be $85,400 [$100,000 - $14,600 standard deduction for 2024]

If you don't tell the jobs about each other (by checking box 2c, for example), then each job will subtract the full standard deduction of $14,600 from your expected wages and then calculate your taxes due for withholding. Your wages will be withheld as if your taxable income was going to be $70,800. This will result in you owing taxes on difference between the $70,800 that your employers calculated and the $85,400 that your actual taxable wages should have been.

Splitting the standard deduction between your jobs eliminates that problem.