Understand Every Line
of Your Paycheck

OASDI stands for Old Age, Survivors, and Disability Insurance — the official name for Social Security. It is deducted because the Federal Insurance Contributions Act (FICA) requires both employees and employers to contribute to the Social Security program. You pay 6.2% of your gross wages up to the annual wage base (which adjusts each year with inflation), and your employer pays a matching 6.2%. This money directly funds your future Social Security retirement benefits, disability benefits if you become unable to work, and survivor benefits for your family. It is not optional — every W-2 employee in the US pays this. Self-employed individuals pay the full 12.4% themselves as part of self-employment tax.

The difference between gross pay and net pay is the sum of all your deductions. A typical employee might see: federal income tax (10–22% depending on bracket), Social Security (6.2%), Medicare (1.45%), state income tax (0–10% depending on state), health insurance premium ($100–$500/month), dental and vision insurance, 401k contribution if enrolled (often 3–15% of salary), and possibly other deductions like FSA, parking, or union dues. When you add all of these up, it's common for net pay to be 65–75% of gross pay. Use the paste decoder to see your exact breakdown — it will show you precisely where every dollar of the difference is going.

FWT stands for Federal Withholding Tax — also called Federal Income Tax or FIT. This is the portion of federal income tax your employer withholds from each paycheck and sends to the IRS on your behalf. The amount is calculated based on your gross wages, your filing status (single, married filing jointly, etc.), and the allowances or adjustments you specified on your W-4 form. At the end of the year, you reconcile this against your actual tax liability when you file your tax return. If too much was withheld, you get a refund. If too little, you owe the difference. You can adjust FWT by submitting a new W-4 to your employer at any time.

YTD stands for Year-to-Date. It shows the cumulative running total of a specific amount — earnings, a deduction, or tax — from January 1 of the current year through your most recent paycheck. For example, if your YTD federal withholding shows $4,800 and you're in September, that means you've had $4,800 in federal income tax withheld from your paychecks so far this year. YTD resets to zero every January 1. It's one of the most useful columns on your pay stub because it lets you track annual totals without waiting for your W-2. Your YTD gross pay at year-end will closely match Box 1 on your W-2, and your YTD federal withholding will match Box 2.

FICA (Federal Insurance Contributions Act) is the law — it's the federal legislation that mandates payroll taxes for Social Security and Medicare. OASDI is one of those taxes — specifically the Social Security component. So FICA is the umbrella term, and OASDI and Medicare are the two taxes it requires. When your pay stub shows FICA as a single line, it's combining both OASDI (6.2%) and Medicare (1.45%) into a single 7.65% deduction. When your stub lists them separately, you'll see OASDI and MED or Medicare as individual line items. Both result in the same total amount — the presentation just differs by payroll system.

Yes, completely. This tool runs entirely in your browser using JavaScript — nothing you type or paste is transmitted to any server. There are no form submissions, no API calls with your data, and no backend database. The code database is loaded when the page loads, and all searching and matching happens locally on your device in real time. Even if you paste your complete pay stub including your name, employee ID, and dollar amounts, none of that information leaves your browser. You can verify this by checking your browser's network tab — you will see zero outbound requests when you use the decoder.

SDI stands for State Disability Insurance. In California, it is a mandatory employee-paid deduction that funds the state's short-term disability and paid family leave programs. If you become unable to work due to a non-work-related illness, injury, or pregnancy, SDI pays approximately 60–70% of your wages for up to 52 weeks. The California SDI rate adjusts annually. SDI is also required in New York, New Jersey, Hawaii, and Rhode Island — each with their own rates and program names (NY calls it DBL, NJ calls it FLI). If you work in any other state and see SDI on your stub, ask your HR department as it may be a voluntary supplemental policy.

GTL stands for Group Term Life insurance imputed income. Here's the situation it reflects: if your employer provides you with group term life insurance coverage exceeding $50,000, the IRS considers the value of coverage above $50,000 to be a taxable fringe benefit — even though you never receive that value as cash. The GTL line on your pay stub represents this imputed income being added to your taxable wages. It increases your reported gross income slightly, which is why you may notice it affects your FICA and income tax withholding even though your actual take-home pay doesn't increase. On your W-2, this amount appears in Box 12 with Code C.

Yes — the codes on pay stubs are largely standardized across the US regardless of which payroll software your employer uses. Whether your company uses ADP, Paychex, Gusto, Workday, Quickbooks Payroll, Rippling, or a custom in-house system, the underlying deduction codes for federal and state taxes are federally and state-mandated and therefore consistent. Benefit codes like 401K, HSA, FSA, STD, and LTD are also highly standardized. The only codes that may differ are company-specific benefit categories that employers create themselves — these will be flagged as "unknown" by our decoder, and your HR team will need to clarify them.

Imputed income refers to the taxable value of non-cash benefits your employer provides. The IRS requires that certain employer-provided benefits be counted as income for tax purposes even though you never receive them as money in your pocket. Common examples include: group term life insurance coverage over $50,000 (GTL), the personal use of a company vehicle, employer-paid gym memberships that exceed IRS de minimis limits, and health or dental insurance provided to a domestic partner who is not your tax dependent. You'll see imputed income added to your gross wages on your pay stub, which is why your taxable gross can be higher than your actual gross pay.

Bonuses are classified as supplemental wages by the IRS, and employers are permitted to withhold a flat 22% federal income tax on supplemental wages up to $1 million (37% above that). Your regular paycheck uses a graduated withholding method based on your W-4 and income level, which for many people results in a lower effective rate. This is why your bonus check feels more heavily taxed — the 22% flat rate may be higher than your normal withholding percentage. Importantly, this doesn't mean you owe more tax on bonuses — at year-end, all your income is taxed at your actual bracket rate and you reconcile the difference on your tax return.

Both HSA (Health Savings Account) and FSA (Flexible Spending Account) let you set aside pre-tax money for medical expenses, but they have important differences. An HSA is only available if you're enrolled in a High-Deductible Health Plan (HDHP), but the money rolls over indefinitely year after year — unused funds stay in your account and can even be invested. An FSA is available with any health plan but typically has a "use-it-or-lose-it" rule where you forfeit unused funds at year-end (with a small grace period or rollover option in some plans). HSAs are generally considered superior long-term savings vehicles; FSAs are better for predictable, near-term medical expenses.

A GARNISH deduction means your employer has received a legal order — from a court or government agency — requiring them to withhold a portion of your wages and send it directly to a third party. Common reasons for wage garnishment include unpaid child support (the most common), defaulted federal student loans, IRS tax levies for back taxes, and court judgments from creditors. Federal law limits garnishment to a maximum of 25% of your disposable earnings or the amount by which your weekly disposable income exceeds 30 times the federal minimum wage — whichever is less. Child support orders can take up to 50–65% under certain circumstances. If you see GARNISH on your stub for the first time and weren't expecting it, contact your HR or payroll department immediately for documentation of the order.

Yes — Social Security tax (OASDI) has an annual wage base limit. Once your cumulative earnings for the year exceed this threshold (which adjusts annually for inflation), Social Security withholding stops for the remainder of the year. Medicare tax, however, has no wage cap — you pay 1.45% on every dollar you earn, with an additional 0.9% surtax on income over $200,000 ($250,000 for married filing jointly). So if you're a higher earner, you may notice around late fall that your OASDI deduction disappears from your paycheck while Medicare continues. Your YTD Social Security column will stop increasing while Medicare keeps climbing. This is completely normal and expected.

Pre-tax deductions reduce your taxable gross wages before federal and state income taxes are calculated. Common pre-tax deductions include 401k contributions, HSA contributions, FSA contributions, and health/dental/vision insurance premiums (when offered through a Section 125 cafeteria plan). For example, if your gross pay is $5,000 and you have $400 in 401k contributions and $300 in health insurance premiums — both pre-tax — your taxable wages for income tax purposes are $4,300. This is why your W-2 Box 1 (federal taxable wages) is often lower than your total gross earnings for the year. Note: OASDI and Medicare are calculated on gross wages before most pre-tax deductions for retirement, but after Section 125 benefit deductions.

LWT stands for Local Withholding Tax — a city or county income tax levied by your local government on top of federal and state taxes. Not all employees pay this — it only applies if you work in (or sometimes live in) a city or county that imposes a local income tax. Cities that have local income taxes include New York City, Philadelphia, Detroit, Columbus, Kansas City, and several others. Rates are typically 1–4%. If you see LWT or a city abbreviation (like NYC, PHILA, or KC) on your stub, it's this local tax. It appears in Box 19 of your W-2 and may require a separate local tax return.

The current database covers 150+ pay stub codes across five categories: Federal Tax (OASDI, FICA, FWT, FIT, MED, Medicare, SSWT), State & Local (SWT, SIT, SDI, SUI, LWT), Benefits (401K, 403B, ROTH, HSA, FSA, COBRA, STD, LTD, GTL, DENTAL, VISION, MED INS, LIFE INS, EAP, SECTION 125, TSA, PARKING), Pay Types (REG, OT, PTO, VAC, HOLI, BONUS, COMM, TIPS, GROSS, NET), and Other (YTD, GARNISH, LEVY, CHILD SUP, IMPUTED, MISC, UNION). The database is updated annually with new codes and adjusted rates. If you encounter a code not in our database, it's flagged as unknown and you're advised to check with your payroll department.