FIT Taxable Wages — What Counts as Taxable Income

FIT taxable wages is the amount on your pay stub subject to federal income tax. It differs from your gross pay because pre-tax deductions reduce it.

What Are FIT Taxable Wages?

FIT taxable wages (Federal Income Tax taxable wages) is the portion of your earnings subject to federal income tax withholding. This number appears on your pay stub and is usually less than your gross pay because certain pre-tax deductions reduce it.

Understanding FIT taxable wages is critical because it determines how much federal tax is withheld from each paycheck. If you see a discrepancy between your gross pay and FIT taxable wages, it typically means you have pre-tax deductions working in your favor.

How FIT Taxable Wages Are Calculated

The formula is straightforward:

FIT Taxable Wages = Gross Pay − Pre-Tax Deductions

Common pre-tax deductions that reduce your FIT taxable wages include:

  • Traditional 401(k) contributions — the most impactful deduction for most workers. A $500/paycheck contribution reduces your FIT taxable wages by $500 each period.
  • Health insurance premiums — employer-sponsored medical, dental, and vision premiums paid by the employee are typically pre-tax under Section 125 cafeteria plans.
  • HSA contributions — Health Savings Account contributions (up to $4,300 individual / $8,550 family in 2025) are pre-tax.
  • FSA contributions — Flexible Spending Account elections for healthcare or dependent care expenses.
  • Commuter benefits — pre-tax transit and parking benefits up to $325/month (2025).

FIT Taxable Wages vs. Other Wage Types on Your Pay Stub

Your pay stub may show several different wage figures. Here is how they differ:

Wage TypeWhat It MeansPre-Tax 401(k) Deducted?
Gross PayTotal earnings before any deductionsNo
FIT Taxable WagesSubject to federal income taxYes
SS Taxable WagesSubject to Social Security tax (up to $176,100)Yes
Medicare Taxable WagesSubject to Medicare tax (no cap)Yes
State Taxable WagesSubject to state income tax (varies by state)Usually yes

Why FIT Taxable Wages Matter for Your Tax Return

Your W-2 Box 1 shows your annual FIT taxable wages. This is the starting point for your federal tax return (Form 1040). If it does not match your expectations, review your pre-tax deduction amounts. The most common reasons for a discrepancy between gross pay and Box 1 are 401(k) contributions, health insurance premiums, and HSA/FSA contributions.

💡 Pro tip: Compare your last pay stub’s year-to-date FIT taxable wages with your W-2 Box 1. They should match. If they do not, contact your payroll department before filing your tax return.

Frequently Asked Questions

FIT stands for Federal Income Tax. FIT taxable wages is the portion of your earnings subject to federal income tax withholding. It equals your gross pay minus pre-tax deductions like 401(k) contributions and health insurance premiums.
Pre-tax deductions (401k, HSA, health insurance, FSA) are subtracted from gross pay before calculating federal income tax. This reduces your FIT taxable wages below your gross pay, which is a tax benefit.
Yes. Your W-2 Box 1 (Wages, tips, other compensation) should equal your total FIT taxable wages for the year. This is the amount used to calculate your federal income tax on your annual tax return.
Increase pre-tax deductions: contribute more to a traditional 401(k) (up to $23,500 in 2025), maximize HSA contributions ($4,300 individual), enroll in an FSA, or increase health insurance contributions through your employer.