Your First H-1B Paycheck After OPT: Why FICA Starts on Your Status Date and How to Check It

Social Security and Medicare should start the day your H-1B status takes effect, not the day USCIS approved it. Here is how to check that first split paycheck line by line.

Part of our guide to US taxes on F-1, OPT and H-1B.

FICA after OPT to H-1B starts on the day your H-1B status takes effect. For a cap case filed as a change of status, that is the validity start date printed on your I-797A approval notice, usually October 1. The approval date alone does not start it, and neither does January 1 of next year. Before that date, OPT and cap-gap pay is generally exempt from Social Security and Medicare while you are a nonresident alien. From that date, 6.2% Social Security and 1.45% Medicare come out of your pay, whatever your income-tax residency.

Status line, as of November 1, 2026: the student FICA exemption in IRC 3121(b)(19) is in effect and unchanged, and so is the cap-gap rule (since 2025-01-17). The OPT Fair Tax Act (S. 2940 / H.R. 8972), which would end the OPT FICA exemption, is only introduced and referred. A 2027 Social Security wage base of $192,300 is scheduled.

When does FICA start after OPT to H-1B?

FICA starts on your H-1B status effective date, the "valid from" date on your I-797A, not the approval date. Pay for work done before that date as a nonresident F-1 student, cap-gap included, stays exempt. Pay for work on and after it owes 6.2% Social Security and 1.45% Medicare, even if you are still a nonresident for income tax. Only a pay period that straddles the date needs a closer look.

The exemption is narrow. IRS Publication 519 (2025 edition) says that, generally, "services performed by you as a nonresident alien temporarily in the United States as a nonimmigrant under subparagraph (F), (J), (M), or (Q)" of the immigration statute "are not covered under the social security program if the services are performed to carry out the purpose for which you were admitted to the United States." It has two exits, and whichever comes first ends it. The IRS page on foreign student liability for Social Security and Medicare taxes (last reviewed 2026-08-18) names both:

• "The exemption does not apply to F-1, J-1, or M-1 students who change to another immigration status which is not exempt or to a special protected status." H-1B is not an exempt status.
• "The exemption does not apply to F-1, J-1, or M-1 students who become resident aliens." That is the five-calendar-year rule, which can end the exemption while you are still on OPT; see when F-1 students start paying FICA.

Common misconception: "I am still a nonresident alien for 2026, so my H-1B pay should be FICA-free." Correction: nonresident status is only half the test. The exemption covers work performed as an F-1 student. H-1B work is not F-1 work, so FICA applies from your first H-1B day, resident or not.

Who owes FICA on which wages (as of 2026-11)

Is FICA withheld during cap-gap?

Generally no. Cap-gap keeps you in F-1 status, so if you are a nonresident alien the student exemption continues until your H-1B status begins, and payroll should treat you exactly as it did on OPT.

The USCIS cap-gap page says the rules "allow certain students with a pending or approved cap-subject H-1B petition to remain in F-1 status during the cap-gap period," ending April 1 of the fiscal year requested or the approved petition's start date, "whichever is earlier." Work permission is extended only if your OPT was still valid when the petition was filed: USCIS says a student already in the 60-day grace period gets the status extension but "will not be authorized to work." Your proof is an updated I-20 from your DSO, which USCIS says "serves as proof of continued employment authorization"; give HR a copy. See our cap-gap extension explainer.

Three edge cases move the date payroll should use:

• USCIS approves after October 1. Do not assume October 1. Read the validity start date on the I-797A; your notice, not the date you requested, governs.
• Your petition asked for consular notification. You get an I-797B instead of an I-797A, cap-gap does not apply, and H-1B status starts when CBP admits you in H-1B status, so the admission date on your I-94 is your FICA date.
• Your petition is cap-exempt. There is no cap-gap for cap-exempt petitions (8 CFR 214.2(f)(5)(vii)). FICA starts on the H-1B start date on your notice.

If a petition is denied, withdrawn, revoked or rejected, cap-gap ends automatically; take that to your DSO and an immigration attorney, not payroll.

The paycheck that straddles October 1: a worked example

Say you are paid every two weeks, $4,000 a check (a round number for arithmetic, not a market salary). The pay period runs Monday 2026-09-21 to Sunday 2026-10-04 and is paid Friday 2026-10-09. Your I-797A shows H-1B validity from Thursday 2026-10-01, so 8 of the 10 workdays fell in F-1 status and 2 in H-1B status.

The pay date does not decide: on our reading of Publication 519, the exemption attaches to work done as an F-1 nonresident, so a check paid in October does not make September work taxable.

What decides a mixed check is a pay-period rule in the tax code. IRC 3121(c) says that if the services in "one-half or more of any pay period" are covered employment, all of that period's services count as employment; if more than half are not, none do. It applies to pay periods of 31 days or less, and Treasury Regulation 31.3121(c)-1 measures the half by time worked. Many payroll systems prorate by days instead, so the same check can come out four ways.

One straddling check, four treatments (our arithmetic, rates as of 2026-11)

The first three differ by less than $90. The last row is the error to catch: it taxes eight days of F-1 work. The pay-period rule cuts both ways, on our reading: if most of a period's time is H-1B work, the whole check counts, F-1 days included. Ask payroll in writing which method it uses, and take a disagreement to a tax professional who handles nonresident returns. Every later, all-H-1B check owes full FICA.

How to check your first H-1B paycheck

Do this before the straddling check is paid, then again when it arrives.

1. Find your status date on Form I-797A, the validity start of the approved change of status. If you entered on an H-1B visa, download your I-94 from the CBP I-94 website and use the admission date.
2. Email HR or payroll that date with a copy of the I-797A, and ask them to confirm in writing the date your FICA exemption ends in the payroll system.
3. Open the pay stub for the straddling period and find the Social Security (OASDI) and Medicare lines.
4. Divide the Social Security line by 0.062 and the Medicare line by 0.0145. On the straddling check, the result should match the method payroll named; your whole gross pay is a red flag unless most of that period was H-1B time. On the first all-H-1B check, it should be close to gross pay (pre-tax cafeteria-plan deductions, such as health premiums, can lower it).
5. Check the year-to-date columns. Checks covering only OPT or cap-gap work should show no Social Security or Medicare.
6. Compare Boxes 3 and 5 of your 2026 Form W-2 when it arrives early in 2027. Social Security and Medicare wages should reflect only H-1B-period pay, while Box 1 normally includes your OPT pay as well.
7. Keep every 2026 pay stub. Publication 519 asks for pay statements covering the exempt period if you claim a refund.

What if my employer withheld FICA before October 1?

You are owed the excess, and your employer is the first stop. A common cause is payroll switching you on the approval date: if your I-797A arrived on 2026-06-15 with an October 1 start, seven full biweekly $4,000 checks would each lose $306 you did not owe, $2,142 in all (hypothetical, our arithmetic).

IRS Publication 15 tells employers: "If you withheld more than the correct amount of income, social security, or Medicare tax from wages paid, repay or reimburse the employee the excess." Correcting a past year also means a Form W-2c.

1. Ask payroll in writing to refund the FICA taken from pay for work before your status date, citing your I-797A and the pay periods.
2. File Form 843 with the IRS if the employer will not or cannot refund it in full. The Form 843 instructions set the filing deadline, so do not let it sit.
3. Attach Form 8316 and the Publication 519 list: your W-2, a copy of your visa, your I-94, your complete I-20, your Form I-766 (EAD) if you were on OPT, a statement from your employer on what it refunded (or Form 8316 saying it will not), and pay statements for the exempt period.
4. Mail the claim to the Ogden, UT 84201-0038 address in Publication 519, after checking the current instructions.

Our guide to claiming an OPT FICA refund with Forms 843 and 8316 walks through the paperwork.

What if no FICA was withheld after my H-1B start?

Then the tax was still due, and payroll will usually catch up. Publication 15 tells employers who under-withheld that they "can make it up from later pay to that employee. But you're the one who owes the underpayment," meaning the employer answers to the IRS for it. Expect a catch-up deduction from a later check, and ask payroll when and how much. A straddling check left untaxed under the pay-period rule is not an under-withholding, on our reading.

Can I get FICA back for the OPT part of the year?

Yes, if it was withheld from pay for work you did as a nonresident F-1 student, cap-gap included. No, if it came from H-1B pay, or from OPT pay earned after you became a resident alien, because that FICA was correct. Leaving the US later does not turn correct FICA into a refund. Whether US credits can ever be combined with home-country coverage depends on a totalization agreement: SSA lists 31 agreements (Romania's took effect 2026-09-01), and none is with India or China.

Does my tax filing change in the switch year?

Often, but for a different reason. FICA follows your immigration status; income-tax residency follows the substantial presence test, so the two can disagree for a whole year. Our guide to how H-1B status affects your taxes explains the split.

Switch-year patterns for an H-1B start of 2026-10-01 (our reading of IRS Publication 519, as of 2026-11)

The first-year choice needs presence "for at least 31 days in a row" and for 75% of the days from then to year-end, not counting exempt-individual days, so October 1 is the earliest start. See the dual-status return in your first US year. A 2026 Form 1040-NR with withheld wages is due 2027-04-15 (our arithmetic; as of 2026-11-01 the posted Form 1040-NR instructions are the 2025 edition). Whether the choice helps is a question for a tax professional who prepares nonresident returns.

Does the Social Security wage base matter in your switch year?

Rarely in 2026. On our reading, exempt OPT pay is not Social Security wages, so only your October-to-December H-1B pay counts toward the 2026 base of $184,500 (maximum employee tax $11,439). The 2027 base is scheduled at $192,300, a maximum of $11,922.60, per SSA's Federal Register notice (2026-10-26). Medicare has no cap; an extra 0.9% is withheld above $200,000. Changing H-1B employers restarts the count; see H-1B taxes when you change employers mid-year.

Common mistakes

• Starting FICA on the approval date. A June I-797A with an October 1 start changes nothing until October 1.
• Taxing the whole straddling check because of its pay date. The work dates decide, and a mixed pay period follows the IRC 3121(c) half-time rule (our reading).
• Assuming October 1 when your notice says otherwise. A late approval or a consular entry moves the date.
• Treating nonresident status as a FICA exemption on H-1B. The exemption is for F-1 work only.
• Forgetting the five-calendar-year rule. If you were already a resident alien on OPT, that FICA was correct.
• Going straight to the IRS. Form 843 comes after you ask your employer, with pay statements for the exempt period.

Frequently asked questions

When does FICA start after switching from OPT to H-1B?

On the date your H-1B status takes effect, the validity start date on your I-797A approval notice, usually October 1 for a cap case. Approval alone does not start it, and neither does January 1. As of November 1, 2026, the student exemption in IRC 3121(b)(19) is unchanged and ends with the change to H-1B, whatever your income-tax residency.

Is FICA withheld during cap-gap?

Generally no, if you are still a nonresident alien. Cap-gap keeps you in F-1 status until April 1 of the fiscal year requested, or the petition start date if earlier, and extends OPT work permission if your OPT was valid when the petition was filed, so the student exemption continues until H-1B status begins. Cap-exempt petitions get no cap-gap, as of November 1, 2026.

What if my employer withheld FICA before October 1?

Ask payroll to refund the Social Security and Medicare taken from pay for work before your H-1B start date, because IRS Publication 15 tells employers to repay excess withholding. If the employer will not refund it in full, file Form 843 with Form 8316 and the documents IRS Publication 519 lists, including pay statements for the exempt period.

Does my tax filing change in the switch year?

Often, but not because of FICA. FICA follows your status change, while income-tax residency follows the substantial presence test. If all your earlier F-1 days were exempt, an October 1, 2026 switch usually leaves 2026 as a nonresident year on Form 1040-NR (our reading of IRS Publication 519), unless you qualify for and make the first-year choice to file as dual-status.

Can I get FICA back for the OPT part of the year?

Yes, if FICA was taken from pay for work you did as a nonresident F-1 student, cap-gap included. Ask your employer first, then file Form 843 with Form 8316. FICA withheld from H-1B pay is correct and is not refundable just because you are a nonresident for income tax.

Bottom line

Your I-797A sets the date FICA starts; your pay stubs show whether payroll used it. Take cap-gap and I-20 questions to your DSO, petition questions to an immigration attorney, and the switch-year return to a tax professional. Your own I-797A, I-94 and I-20 govern over anything published here.

How we checked this: on 2026-11-01 we read the IRS foreign-student FICA page (last reviewed 2026-08-18), IRS Publication 519 (2025 edition) and Publication 15 (2026), the Form 843 instructions, IRC 3121(c) and Treasury Regulation 31.3121(c)-1, the USCIS cap-gap page (updated 2025-01-17), SSA's totalization list and SSA's 2027 wage-base notice (2026-10-26). This is general information, not legal or tax advice.

Sources

• IRS, Foreign student liability for Social Security and Medicare taxes
• IRS, Publication 519, U.S. Tax Guide for Aliens
• IRS, Publication 15, Employer's Tax Guide
• IRS, Instructions for Form 843 and Form 8316
• IRS, Instructions for Form 1040-NR
• US Code, 26 U.S.C. 3121, definitions including subsection (c), and Treas. Reg. 31.3121(c)-1
• SSA, POMS GN 01701.005, international social security (totalization) agreements
• USCIS, Cap-gap extension of OPT and F-1 status
• SSA, 2027 wage base notice, Federal Register, 2026-10-26

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