Box 1 on your W-2 is calculated by taking your total cash compensation for the year, subtracting pre-tax deductions that federal income tax doesn’t apply to, and adding the value of any taxable fringe benefits your employer provided. That is why Box 1 almost never matches your gross pay or your final year-to-date earnings on your last pay stub. Knowing which items pull the number down and which push it up is the quickest way to catch a payroll mistake before it becomes a tax problem.
What Gets Added Into Box 1
The starting point is cash: salary, hourly wages, bonuses, commissions, severance, and reported tips.1Internal Revenue Service. About Form W-2, Wage and Tax Statement If it hit your paycheck as taxable earnings, it goes in.
Your employer then adds the value of certain non-cash benefits, often called imputed income. Group-term life insurance is the most common: coverage your employer provides above $50,000 generates a taxable cost that gets added to your wages even though no money changes hands.2Internal Revenue Service. Group-Term Life Insurance Personal use of a company vehicle works the same way. A portion of the benefit, based on your personal mileage, counts as taxable income.
Equity compensation lands in Box 1 when it becomes taxable. Restricted stock units are taxed at vesting. Non-qualified stock options are taxed at exercise, with the spread between the exercise price and the market price treated as ordinary income. Your employer withholds on these amounts and folds them into Box 1 along with regular pay, which is why a big vesting event can make the box look much larger than your base salary would suggest.
A few other additions catch people off guard:
- Moving expense reimbursements are now fully taxable for most employees. The One Big Beautiful Bill Act permanently eliminated the exclusion, so relocation money shows up in Box 1. Active-duty military members moving under permanent change-of-station orders and certain intelligence community employees are the exceptions.3Internal Revenue Service. Publication 15-B (2026), Employers Tax Guide to Fringe Benefits
- Third-party sick pay from a disability insurance carrier is included in Box 1 to the extent it is taxable. If your employer paid the premiums, the benefits are generally taxable. If you paid the premiums with after-tax dollars, they are typically excluded.4Internal Revenue Service. General Instructions for Forms W-2 and W-3
- Employer educational assistance is excluded up to $5,250 per year; anything above that is added to Box 1. The exclusion begins adjusting for inflation in tax years after 2026.5Office of the Law Revision Counsel. 26 USC 127 – Educational Assistance Programs
- Dependent care assistance is tax-free up to $7,500 per household for 2026 ($3,750 if married filing separately), with the excess added to Box 1.
- Adoption assistance is excludable up to $17,670 for 2026, phasing out at higher incomes, and any excess goes in Box 1.
What Gets Subtracted Before Box 1 Is Calculated
Pre-tax deductions are the main reason Box 1 falls below your gross pay. These dollars never enter the Box 1 total because federal income tax does not apply to them.
Traditional Retirement Plan Contributions
Elective deferrals to a traditional 401(k), 403(b), or governmental 457(b) are excluded from Box 1.6Internal Revenue Service. Topic No. 424, 401(k) Plans For 2026, the deferral limit is $24,500, with an additional $8,000 catch-up for employees 50 and older. A higher catch-up of $11,250 applies to employees aged 60 through 63.7Internal Revenue Service. 401(k) Limit Increases to $24,500 for 2026, IRA Limit Increases to $7,500
Health Premiums and Cafeteria Plan Deductions
Most employees pay their share of health, dental, and vision premiums on a pre-tax basis through a Section 125 cafeteria plan.8Office of the Law Revision Counsel. 26 USC 125 – Cafeteria Plans Those premiums come out before Box 1 is calculated, which is often the single biggest reason your taxable wages look smaller than your earnings.
HSA contributions reduce Box 1 whether your employer funds the account directly or you contribute through payroll under a cafeteria plan. For 2026, the HSA limit is $4,400 for self-only coverage and $8,750 for family coverage.9Internal Revenue Service. Publication 969 (2025), Health Savings Accounts and Other Tax-Favored Health Plans Healthcare FSA contributions (up to $3,400 for 2026) and dependent care FSA contributions also reduce Box 1 because they come out of pre-tax salary.
Commuter Benefits
Qualified transportation fringe benefits, including transit passes, commuter van transportation, and qualified parking, are excluded from Box 1 up to $340 per month for 2026.3Internal Revenue Service. Publication 15-B (2026), Employers Tax Guide to Fringe Benefits
Deductions That Don’t Lower Box 1
Some payroll deductions are taken after federal income tax is calculated, so they shrink your take-home pay without shrinking Box 1. Roth 401(k) and Roth 403(b) contributions are the big one. Roth money is contributed with after-tax dollars because the tax benefit comes later, when qualified withdrawals are tax-free, so your Roth contributions stay in Box 1.10Internal Revenue Service. General Instructions for Forms W-2 and W-3 (2026) Union dues, wage garnishments, and after-tax disability or life insurance premiums fall in the same category.
Why Box 1 Doesn’t Match Box 3 or Box 5
Federal income tax, Social Security tax, and Medicare tax each define taxable wages differently, which is why your three wage boxes rarely agree.
Social Security tax applies only up to an annual wage cap. For 2026 that cap is $184,500.11Internal Revenue Service. Topic No. 751, Social Security and Medicare Withholding Rates12Social Security Administration. 2026 Cost-of-Living Adjustment (COLA) Fact Sheet If you earn more than the cap, Box 3 stops at that figure while Box 1 keeps going.
Medicare tax has no wage cap, so Box 5 is never limited the way Box 3 is.11Internal Revenue Service. Topic No. 751, Social Security and Medicare Withholding Rates Box 5 is often higher than Box 1 because most pre-tax retirement contributions that reduce Box 1 are still subject to Medicare tax. An additional 0.9% Medicare tax kicks in once your wages pass $200,000 in a calendar year.13Social Security Administration. Social Security and Medicare Tax Rates
Non-qualified deferred compensation moves in the opposite direction. Deferrals are generally hit with Social Security and Medicare tax when you perform the services, but the income doesn’t appear in Box 1 until a later year when it’s paid out. That can make Box 3 or Box 5 larger than Box 1 even for employees well below the Social Security cap.
How to Check Your Box 1 Against Your Pay Stub
The simplest reconciliation uses your final pay stub of the year. Start with your year-to-date gross pay. Subtract every pre-tax deduction on the stub: traditional 401(k) or 403(b) contributions, cafeteria plan health premiums, HSA contributions, FSA contributions, and commuter benefits. Then add any taxable fringe benefits your employer imputed to you that aren’t already in the gross pay figure: group-term life insurance over $50,000, personal use of a company car, or stock compensation reported separately. The result should equal Box 1.
If the numbers don’t line up, look for mid-year changes before assuming an error. Switching health plans, changing your contribution rate, or receiving a retroactive adjustment can all shift Box 1 in ways that aren’t obvious from one pay stub. When the gap still can’t be explained, go to payroll before you file.
What to Do If Box 1 Is Wrong
Your employer must deliver your W-2 by January 31. For the 2025 tax year, the deadline falls on February 2, 2026, because January 31 is a Saturday.14Internal Revenue Service. Publication 509, Tax Calendars If Box 1 is wrong, ask your employer to issue a corrected form. Employers use Form W-2c to fix a previously filed W-2.15Internal Revenue Service. About Form W-2c, Corrected Wage and Tax Statements
If your employer won’t correct the form or can’t do it in time, you can file using Form 4852 as a substitute W-2, entering the wage and tax figures from your own records.16Internal Revenue Service. About Form 4852, Substitute for Form W-2 Returns filed with Form 4852 can take longer to process because the IRS may verify the numbers, so a W-2c from your employer is the faster route whenever you can get one.