W2 Section 125: What It Is and How to Check Your Numbers
W2 Section 125 refers to the pre-tax benefit deductions your employer took through its cafeteria plan, which lower the wages shown in Box 1, Box 3 and Box 5 of Form W-2. This guide shows where Section 125 appears on a W-2, why Box 1 and Box 3 can differ, a three-step method to check your numbers against your final pay stub of the year, and what to do when they do not match.
- Employee Social Security and Medicare tax is 7.65% (6.2% plus 1.45%), so every $1,000 of Section 125 saves $76.50 in payroll tax, per IRS Topic No. 751 (2026).
- The Social Security wage base is $184,500 for 2026 earnings, which caps the Box 3 amount, per IRS Topic No. 751 (2026).
- A 401(k) deferral lowers Box 1 but still counts for Social Security and Medicare, so Box 1 can sit $3,000 or more below Box 3 with no Section 125 at all, per IRS Topic No. 424 (reviewed September 24, 2026).
- Information once reported in Box 14 now goes in Box 14a on the 2026 Form W-2, per the IRS General Instructions for Forms W-2 and W-3 (2026).
You are holding a W-2 that mentions Section 125, or a pay stub with a Section 125 line, and the numbers do not seem to add up. W2 Section 125 is your pre-tax benefit total, and it is one reason your taxable wages are lower than your pay. This guide shows where it appears, why Box 1 and Box 3 can differ, and a three-step check you can do with a calculator.
Reviewed by a licensed benefits professional. Last reviewed: October 10, 2026.
What is section 125 on a W-2?
Section 125 on a W-2 is your share of benefits paid with pay that was never taxed, through your employer's cafeteria plan. The name comes from Section 125 of the Internal Revenue Code.
A cafeteria plan is a written employer plan that lets you choose between cash and certain benefits, such as health insurance premiums, dental and vision premiums, a health FSA or a dependent care FSA. IRS Publication 15-B (2026) says a cafeteria plan gives participants a chance to receive qualified benefits on a pre-tax basis.
Benecor Health's Section 125 cafeteria plan guide explains how employers set one up. Summit Health Benefits also has a plain-English page on what Section 125 means on a W-2 from the employer side.
Where does section 125 show up on my W-2?
Section 125 shows up as a lower number in Boxes 1, 3 and 5, and sometimes as an optional note in Box 14a. Form W-2 has no box labeled Section 125, so the deduction appears by its effect.
| W-2 box | What it shows | Effect of Section 125 |
|---|---|---|
| Box 1 | Wages for federal income tax | Lowered by your pre-tax benefits |
| Box 3 | Social Security wages | Lowered by your pre-tax benefits, up to the wage base |
| Box 5 | Medicare wages | Lowered by your pre-tax benefits |
| Box 14a | Other, set by the employer | May list a Section 125 total, but it is optional |
The IRS General Instructions for Forms W-2 and W-3 (2026) say information that was reported in Box 14 will now be reported in Box 14a. Employers label Box 14a themselves, so you may see Sec 125, S125, Cafe 125 or nothing. Benecor's guide to W-2 Box 14 and Section 125 covers the common labels.
Why is Box 1 lower than Box 3 on my W-2?
Box 1 is lower than Box 3 when you made 401(k) deferrals, because deferrals are removed from income tax wages but not from Social Security and Medicare wages. IRS Topic No. 424 (reviewed September 24, 2026) says deferred amounts are included as wages subject to withholding for Social Security and Medicare taxes, and are not in Box 1.
Section 125 amounts come out of all three boxes. A 401(k) deferral comes out of Box 1 only. That difference is the key to checking your numbers.
Box 3 can also stop growing. The Social Security wage base is $184,500 for earnings in 2026 (IRS Topic No. 751, 2026). If you earn more than the base for your W-2 year, Box 3 will be capped, so check the base for that year.
How do I check my W-2 section 125 numbers?
Check your numbers in three steps. Start with your gross pay, subtract Box 3, and compare the result to your final pay stub of the year.
- Find your gross pay. Use the year-to-date gross on your last pay stub of the year.
- Subtract Box 3. Gross pay minus Box 3 equals your pre-tax benefits that avoid Social Security tax, mainly Section 125. If you earned above the Social Security wage base, skip this step and use Box 5 instead.
- Compare to your Section 125 line. Add every Section 125 line on that last pay stub, such as medical, dental, vision and FSA. The total should match step 2.
Here is a worked example. The employee is hypothetical, with $62,000 in gross pay, $5,000 in Section 125 deductions and a $3,000 401(k) deferral. FICA rates are 6.2% for Social Security and 1.45% for Medicare (IRS Topic No. 751, 2026).
| Item | Calculation | Result |
|---|---|---|
| Box 1 wages | $62,000 - $5,000 - $3,000 | $54,000 |
| Box 3 wages | $62,000 - $5,000 | $57,000 |
| Box 5 wages | $62,000 - $5,000 | $57,000 |
| Box 4 Social Security tax | $57,000 x 6.2% | $3,534.00 |
| Box 6 Medicare tax | $57,000 x 1.45% | $826.50 |
| Check: gross minus Box 3 | $62,000 - $57,000 | $5,000 |
| Check: gross minus Box 1 | $62,000 - $54,000 | $8,000 |
The check works. Gross minus Box 3 is $5,000, the Section 125 total. Gross minus Box 1 is $8,000, which is Section 125 plus the 401(k). If the first difference is higher than your pay stub total, something else is lowering Box 3, or the pay stub is missing a line.
This method has limits. Other pre-tax benefits, such as commuter benefits or HSA contributions through a cafeteria plan, can also lower Box 3. IRS Publication 15-B (2026) says that in most cases excluded benefits are not subject to income tax withholding, Social Security tax or Medicare tax. Add those lines to your step 3 total.
What if my W-2 section 125 numbers do not match?
When the numbers do not match, ask payroll for a line-by-line list before you assume an error. Most differences come from a pre-tax item you forgot, a mid-year change or a labeling choice by the employer.
| What you see | Likely reason | What to ask payroll |
|---|---|---|
| Box 3 lower than gross minus Section 125 | Another pre-tax benefit, such as commuter or HSA through the plan | A list of every pre-tax deduction by code |
| Box 1 much lower than Box 3 | 401(k) or other retirement deferrals | Year-end deferral total |
| Box 14a blank | Box 14a is optional | Nothing, the amount is still in Boxes 1, 3 and 5 |
| Pay stub total higher than W-2 difference | Mid-year change or a missed paycheck | Corrected W-2 if payroll made an error |
If payroll made an error, the employer can issue a corrected W-2. Keep your last pay stub, your benefit enrollment confirmation and the written plan summary together. Our guide to the Section 125 wellness deduction explains a deduction some workers do not recognize.
Can I stop or change my section 125 deduction?
Usually not in the middle of the year. Section 125 elections are generally locked for the plan year, and changes are allowed only after specific events recognized under 26 CFR 1.125-4, such as marriage, a birth or loss of other coverage. IRS Publication 15-B (2026) describes the same rule for cafeteria plan elections.
How do I ask my employer about my section 125 deduction?
Send payroll or HR a short written request, and keep the answer. Copy and paste this email, and fill in the brackets.
If you still cannot match a deduction after payroll answers, request a case review with a Benecor benefits expert. Benecor's guides to Less Sec 125 on a W-2 and to Section 125 on a wage statement cover the other labels you may see.
Sources: IRS Topic No. 751, Social Security and Medicare withholding rates (2026); IRS Topic No. 424, 401(k) plans (reviewed September 24, 2026); IRS Publication 15-B, Employer's Tax Guide to Fringe Benefits (2026); IRS General Instructions for Forms W-2 and W-3 (2026); 26 CFR 1.125-4, Permitted election changes (2026); Internal Revenue Code Section 125 (2026).
Frequently asked questions
- What is Section 125 on a W-2?
- Section 125 on a W-2 is the total of your pre-tax benefit deductions taken through your employer's cafeteria plan, such as health premiums or an FSA. It lowers your Box 1, Box 3 and Box 5 wages. Box 14a may list it, but that box is optional.
- Is Section 125 taxable on my W-2?
- Section 125 benefits are generally not taxed when they pay for qualified benefits such as health premiums or an FSA. IRS Publication 15-B (2026) says a cafeteria plan lets you receive qualified benefits on a pre-tax basis. You do not add the amount back to your income.
- Why is my W-2 Box 3 higher than Box 1?
- Box 3 is usually higher than Box 1 when you made 401(k) deferrals. IRS Topic No. 424 says deferrals count as wages for Social Security and Medicare taxes but are not in Box 1. Section 125 lowers both boxes.
- How do I find my Section 125 total on my W-2?
- Subtract your Box 3 wages from your gross pay for the year. If you have no other pre-tax items that avoid Social Security tax, the result is your Section 125 total. Then compare it to the Section 125 lines on your last pay stub.
- Can my employer leave Section 125 out of Box 14a?
- Yes. Box 14a is set by the employer, and many employers leave it blank (IRS General Instructions for Forms W-2 and W-3, 2026). The deduction is still reflected in Boxes 1, 3 and 5.
- Can I cancel a Section 125 deduction mid-year?
- Usually not. Section 125 elections are generally locked for the plan year, and mid-year changes need a qualifying event under 26 CFR 1.125-4 (2026). Ask HR for the plan's election change rules in writing.
Continue reading
- W-2 Box 14: What Section 125 Means on Your W-2 — Section 125 Plan
The plain-English employee version — what 'Section 125' in Box 14 actually does to your paycheck, and the exact employer reporting standard.
- Less Sec 125 and Other Cafe 125 on Your W-2, Explained — Employee Benefits
Less Sec 125 and Other Cafe 125 on a W-2 are pre-tax deductions from your Section 125 plan. See what they cover, what they save and how to check them.
- What Is Sec 125 on a W-2? Plain-English Guide — Employee Benefits
Sec 125 on a W-2 means pre-tax benefit deductions, not extra tax. See where it shows up, what it saves you in real dollars, and when to ask HR.
About the author
Muhammad Mudassir — Co-founder & Health Tech Sales Lead
Muhammad Mudassir, who goes by Moe, is a co-founder and health technology operator focused on Section 125 cafeteria plans and zero-cost employer benefits. He has spent years getting employers enrolled in compliant cafeteria plans, onboarding nationwide workforces into the WoW Health and UnifyWell ecosystems, and translating the mechanics of FICA recapture into language that HR, finance, and ownership can act on.