Circular E in Plain English: What Publication 15 Tells Small Employers About Withholding, Deposits, and Forms 941 and W-2

You hired your first employee. The offer letter is signed, the W-4 is on your desk, and then reality hits: how much federal tax do you actually withhold from that first paycheck, when do you send it to the IRS, and what forms prove you did it right? Get any of those steps wrong and the penalties stack fast — 2% to 15% for late deposits alone.

Publication 15, also called Circular E, is the IRS's single employer playbook for exactly this. It is not light reading at 70-plus pages, but every answer about federal income tax withholding, Social Security and Medicare, deposit schedules, and quarterly and year-end filings lives there. Here is the practical translation.

What Circular E Actually Is (and Who Needs It)​

Publication 15 (Circular E), Employer's Tax Guide, is the IRS's annually updated rulebook for any business or household employer that pays wages subject to federal withholding. If you have employees — full-time, part-time, seasonal, or even one part-time barista — you are an employer for this purpose.

It covers:

• Who is an employee for federal purposes and why it matters that a 1099 contractor is not covered here
• What counts as wages (salary, bonuses, tips, taxable fringe benefits, certain reimbursements)
• How to withhold federal income tax, Social Security, and Medicare correctly
• When and how to deposit those taxes
• Which returns to file — Form 941 every quarter, Form 940 annually for FUTA, and Forms W-2 and W-3 at year-end

Two companion publications extend it: Publication 15-A covers supplemental wages and more complex withholding situations, and Publication 15-B covers the tax treatment of fringe benefits like health coverage and group-term life. For 90% of small businesses, Publication 15 itself is enough day to day.

If you use a payroll provider, you still need to understand Circular E. The provider executes your instructions, but you remain legally responsible for timely deposits and accurate returns.

The Three Taxes You Withhold or Pay on Every Paycheck​

Every regular paycheck involves three federal components. Circular E tells you the 2026 rates, wage bases, and how to apply them.

1. Federal Income Tax Withholding​

There is no flat rate. You withhold based on the employee's Form W-4, pay frequency, and the IRS withholding tables or percentage-method tables in Publication 15.

Key points for 2026:

• The IRS updates the wage-bracket and percentage-method tables every year for inflation. For 2026, the single standard deduction is $15,000 and the married-joint deduction is $30,000, so the tables shift slightly from 2025. Using last year's tables under-withholds.
• Form W-4 (2020 redesign) no longer uses withholding allowances. Employees now state filing status, dependents, other income, and extra withholding directly. If you still have old W-4s on file, you honor them until the employee submits a new one.
• Two methods are allowed: the wage-bracket method (quick lookup for wages within the table range) and the percentage method (formula-based, better for payroll software). Both give the same result when applied correctly.

Practical tip: When in doubt, add the employee's extra withholding amount from Step 4(c) of the W-4 after you look up the base amount. That extra amount is the most common place small employers forget to add.

2. Social Security (OASDI) — 6.2% Each​

For 2026, you withhold 6.2% of wages for Social Security up to the annual wage base of $176,100 (the base is indexed and reset each January — confirm your payroll software reflects the current year's figure before your first run). You as employer match another 6.2%. Once an employee crosses the wage base in cumulative wages for the year, you stop withholding Social Security — but keep withholding Medicare.

No W-4 choice affects this. It is a flat percentage up to the cap.

3. Medicare — 1.45% Plus the Extra 0.9%​

You withhold 1.45% of all wages for Medicare with no cap, and you match 1.45%. For wages above $200,000 in a calendar year (regardless of filing status for withholding purposes; the employee sorts out joint vs. single on their own return), you also withhold an Additional Medicare Tax of 0.9% — employee only, no employer match.

That $200,000 threshold applies per employee, per payroll, without regard to spouse wages. You start the extra 0.9% in the pay period the employee first crosses $200,000 and keep applying it the rest of the year.

Quick math for a $60,000 salary paid biweekly:

• Social Security: $2,307.69 × 6.2% = $143.08 withheld, $143.08 employer share
• Medicare: $2,307.69 × 1.45% = $33.46 each side
• Federal income tax: depends on W-4 — for a single filer with no adjustments using 2026 tables, roughly $180–$210 depending on pre-tax deductions

The takeaway: Social Security and Medicare are mechanical. Federal income tax is where W-4 accuracy matters.

How to Actually Calculate Withholding Without Guessing​

Publication 15 lays out two IRS-approved paths. Pick one and stay consistent.

Option A: Wage-Bracket Tables​

Good for manual payroll with one pay frequency. You find the table for your payroll period (weekly, biweekly, semimonthly, monthly), locate the employee's adjusted wage after subtracting pre-tax 401(k) and Section 125 benefits, then cross-reference filing status. The table gives you the withholding amount.

Limits: Tables only go up to a certain wage amount. Above that, you must use the percentage method.

Option B: Percentage Method​

Better for spreadsheets or software. You:

1. Start with gross wages for the period
2. Subtract pre-tax deductions (401(k), HSA, health premiums)
3. Subtract one payroll period's worth of the standard deduction and tax brackets converted to a per-period basis (the Publication 15 worksheet does this)
4. Apply the graduated rates (10%, 12%, 22%, etc.) to the remainder
5. Add any extra withholding from W-4 Step 4

Most payroll software uses the percentage method under the hood. If you build your own sheet, replicate the Publication 15 worksheet exactly — don't approximate with annual brackets divided by 26.

Don't Forget Pre-Tax Adjustments​

Not every dollar is withholdable. The order matters:

• Reduce federal income tax wages for traditional 401(k), HSA through cafeteria plan, and Section 125 health premiums
• Do not reduce Social Security and Medicare wages for 401(k) (401(k) is still subject to FICA)
• Reduce all three for Section 125 health and dependent-care benefits when properly structured

That one distinction — 401(k) is exempt from income tax withholding but not from FICA — catches many first-time spreadsheets.

Deposit Schedules: The Part That Generates Penalties​

Withholding is not enough. You must deposit what you withheld plus the employer share on the schedule the IRS assigns you.

Monthly vs. Semiweekly — The Lookback Period Decides​

Your deposit schedule is not a choice. It is determined by your total employment taxes reported during the lookback period: the four quarters ending the prior June 30. For 2026, the lookback is July 1, 2024 through June 30, 2025.

• If you reported $50,000 or less in that lookback, you are a monthly depositor: deposits are due by the 15th of the month following the payroll.
• If you reported more than $50,000, you are a semiweekly depositor: payday Wednesday–Friday → deposit by next Wednesday; payday Saturday–Tuesday → deposit by next Friday.

New employers with no lookback history are monthly depositors for their first year by default.

The $100,000 Next-Day Rule​

If you accumulate $100,000 or more in liability on any day, you must deposit by the next business day, and you automatically become semiweekly for the remainder of that calendar year and the next.

The $2,500 Quarterly Escape Hatch​

If your total quarterly liability (Form 941, line 12) is less than $2,500, you may pay with the return instead of making separate deposits — but only if you are a monthly depositor. Semiweekly depositors must still deposit even small amounts.

How to Deposit​

All deposits go through EFTPS (Electronic Federal Tax Payment System). Direct pay from your bank to the IRS via EFTPS is required — mailing a check with the return is no longer accepted for most deposits. Schedule the payment at least one business day before the due date; the settlement date is what counts.

Failure-to-deposit penalties:

• 2% if 1–5 days late
• 5% if 6–15 days late
• 10% if more than 15 days late
• 15% if still unpaid more than 10 days after the first IRS notice

Interest also accrues from the due date. This is why Circular E spends pages on deposit timing.

Forms 941 and W-2: How You Report What You Did​

Form 941 — Quarterly, Every Quarter You Pay Wages​

Form 941 (Employer's Quarterly Federal Tax Return) reconciles what you withheld and what you deposited.

• Due April 30, July 31, October 31, January 31 for calendar quarters. If deposits were timely and in full, you get an extra 10 days.
• You report: total wages, federal income tax withheld, Social Security and Medicare wages and tax (including Additional Medicare), and adjustments for tips and sick pay.
• You also complete Schedule B or use the monthly breakdown on Form 941 if you are a monthly depositor.

Even if you had no wages for a quarter but remain an employer, you file a zero return until you file a final return and check the final-return box.

Form 940 — Annual FUTA​

Separate from Circular E's main focus, but referenced: federal unemployment tax (FUTA) is 6% on the first $7,000 of each employee's wages, with a credit up to 5.4% for timely state unemployment payments. Most employers effectively pay 0.6%. File Form 940 annually by January 31.

Forms W-2 and W-3 — Year-End​

• Furnish W-2s to employees by January 31 (for 2026 wages, that is February 1, 2027, since January 31 is a Sunday — but plan for January 31).
• File W-2 Copy A with the Social Security Administration and transmit Form W-3 by January 31 as well.
• E-file is required if you file 10 or more information returns (W-2s plus 1099s counted together).

Box 1 on the W-2 is federal taxable wages (after pre-tax deductions), Box 3 is Social Security wages (usually higher because 401(k) is not subtracted), Box 5 is Medicare wages. Reconciling those three boxes is the fastest way to spot a withholding setup error.

Five Mistakes Publication 15 Warns About (Without Calling Them That)​

1. Treating an Employee as a Contractor to Avoid Withholding​

Circular E applies to employees. If someone should be an employee under the common-law control test, labeling them a contractor does not remove the withholding obligation — it just makes the liability, plus penalties, land on you later. When the relationship looks like an employee (you set hours, provide tools, control how work is done), withhold.

2. Forgetting Taxable Fringe Benefits​

Employer-paid group-term life over $50,000, personal use of a company car, and certain bonuses and awards are wages for withholding. Publication 15-B lists the valuation rules. Book them as wages in the period the benefit is provided, not at year-end as a surprise.

3. Mishandling Tips​

If you run a restaurant or salon, employees must report tips to you by the 10th of the following month. You withhold income tax and FICA on reported tips and report them on Form 941. You don't pay the employee's share from your pocket — you collect it from the employee's regular wages, and if wages are insufficient, the shortfall carries forward.

4. Not Adjusting for Multiple Jobs or Extra Withholding​

An employee working two jobs may be under-withheld if both employers use the standard tables. The W-4 Step 2 checkbox (or the multiple-jobs worksheet) and Step 4(c) extra withholding exist for this reason. Encourage employees who are under-withheld to update their W-4 rather than facing a balance due.

5. Depositing Late Because You Use Net Pay Date Instead of Liability Date​

The deposit clock starts on payday — the date wages are made available — not the end of the pay period or when you run payroll. A payroll run on Monday for checks dated Friday creates liability on Friday.

What Changed for 2026 That You Should Actually Update​

Circular E is reissued each December. For 2026, review these before your first January payroll:

• Withholding tables — updated for the new standard deduction and bracket inflation adjustments. Replace last year's table immediately.
• Social Security wage base — $176,100 for 2026. Adjust your payroll cap.
• FICA rates unchanged — still 6.2% Social Security, 1.45% Medicare, 0.9% Additional Medicare over $200,000.
• FUTA wage base — still $7,000 federally, but watch state unemployment bases that often run higher (many states are $12,000–$20,000).
• Form W-4 — no redesign for 2026, but remind employees that life changes (marriage, child, second job) should trigger a new W-4.
• E-filing threshold — 10 or more information returns still triggers mandatory e-file for W-2s and 1099s.

The IRS also continues phasing out paper-heavy processes: if you file Forms 941 or 940 on paper, expect slower processing. E-file through IRS-approved software or a provider remains fastest.

A Simple Implementation Checklist for a Small Business With 2–10 Employees​

Before first payroll:

• Get an EIN if you don't have one, register for EFTPS, and confirm your state withholding and unemployment accounts
• Collect signed Forms W-4 and state withholding forms; verify SSNs against the cards to avoid W-2 mismatches
• Decide on pay frequency and stick to it — changing frequency mid-quarter complicates 941 Schedule B

Each payroll:

• Calculate gross, subtract pre-tax benefits in the right order, apply Publication 15 tables, record employer share separately
• Make the deposit on your schedule; keep the EFTPS confirmation number with the payroll record
• Keep a payroll register showing per-employee wages, withholding, and employer tax — this is your audit trail

Each quarter:

• Reconcile payroll register to bank debits to EFTPS; fix variances before filing 941
• File Form 941 even for a zero-wage quarter
• Pay state withholding and state unemployment on their own schedules (not part of Circular E, but equally due)

Each January:

• Reconcile all four 941s to the W-3 totals before you issue W-2s — if they don't match, find the error before employees file
• Furnish W-2s by January 31, file W-2/W-3 with SSA, and file Form 940 for FUTA
• Issue 1099-NEC by January 31 for contractors paid $600+ (different from W-2, but often due the same day)

How Bookkeeping Makes Circular E Painless — or Painful​

Payroll tax mistakes rarely start in the tax tables. They start in the books: one bank account for everything, payroll liabilities lumped into "expenses," and a scramble at quarter-end to reconstruct what was withheld.

Give each payroll tax its own ledger account: federal withholding payable, Social Security payable (employee and employer separated), Medicare payable, and FUTA payable. When you run payroll, credit those payables and debit wage expense and employer payroll tax expense. When you deposit via EFTPS, debit the payables. At any moment, the remaining balance in those payables should equal exactly what you owe but haven't deposited — nothing more.

Reconcile monthly. If your payroll provider debits a single lump sum, split it in your books using the provider's detail report. And keep payroll records for at least four years after the tax was due or paid, whichever is later — Circular E's recordkeeping requirement, not a suggestion.

Good books also surface decisions. Seeing employer Social Security and Medicare as a separate monthly cost (roughly 7.65% of wages up to the cap) clarifies the true cost of a raise or a new hire before you make the offer.

Simplify Your Financial Management​

Getting withholding, deposits, and Forms 941 and W-2 right is really a bookkeeping discipline: track every payroll liability in the right account, deposit on schedule, and reconcile before you file. Beancount.io gives you plain-text accounting that is transparent, version-controlled, and AI-ready — so your payroll payables, deposits, and quarterly reconciliations stay auditable and exactly where you expect them. Get started for free and bring the same rigor to your books that Circular E brings to payroll.