Payroll Tax Filing Checklist

Pull every active employee in Gusto / ADP / Rippling and confirm a current Form W-4 is on file. Cross-check state withholding equivalents (NY IT-2104, CA DE 4, etc.) for any employee who changed work state during the quarter. Missing or stale W-4s default to single / zero — a frequent under-withholding source.

Confirm every new hire from the period has a completed Form I-9 within 3 business days of start, and E-Verify case closure where state law requires it. Tie the HRIS new-hire roster to the payroll system's employee list — orphan records in either system signal a missed onboarding step.

Run the SSA Business Services Online verification on any new SSNs. Confirm home addresses match state of residence — a remote employee who moved states mid-quarter triggers multi-state withholding obligations and is the most common W-2 reissue cause.

Confirm each terminated employee was paid out per the state's final-pay statute (CA: same day for involuntary; many states: next regular payday). Flag any unused PTO payouts that affect taxable wages and FUTA / SUTA totals.

Tie the payroll register's gross-wage total to the wage expense accounts in QuickBooks / NetSuite for the period. Variances usually trace to manual checks posted outside payroll, off-cycle bonus runs, or expense reimbursements miscoded as wages.

Recalculate employer-side Social Security (6.2% to wage base) and Medicare (1.45% + 0.9% Additional Medicare over $200K). Confirm SUI is calculated against each state's wage base — these change annually and are a common Q1 miss.

Verify Section 125 cafeteria, 401(k) deferrals, HSA, and commuter deductions reduced the correct tax bases (FIT vs FICA differ for some). Confirm group-term life over $50K is imputed and GTL imputed income is taxed for FICA. These drive W-2 box 12 codes at year-end.

Walk the controller through each variance and post correcting journal entries before forms are prepared. Document the root cause in the workpaper — repeated variances of the same type suggest a process or mapping issue in the payroll-to-GL integration.

Populate lines 1-15 from the quarterly payroll register. Reconcile line 12 (total taxes after adjustments) to actual deposits made (line 13a) — any imbalance becomes a balance due or overpayment that must be addressed before filing. Confirm Schedule B is attached if you are a semiweekly depositor.

File the appropriate state withholding return (e.g., NY NYS-45, CA DE 9 / DE 9C, IL IL-941) and SUI wage report for every state with active employees. Multi-state employers commonly miss states where one remote employee was hired mid-quarter.

Cover PA local EIT and LST, OH RITA / CCA municipalities, NYC, Philadelphia wage tax, and any other local jurisdictions where employees worked. Locals are the most-missed filings — a single PA employee can trigger filings in three jurisdictions (state, school district, municipality).

Address each review note, repost any required correcting journal entries, and route the revised package back to the partner for re-approval before any e-filing happens.

Verify whether the company is a monthly or semiweekly depositor based on the prior-year lookback period. If accumulated tax liability hits $100K on any day, the next-day deposit rule applies — missing this triggers a 10% penalty.

Initiate the EFTPS payment by 8:00 PM ET the business day before the due date — same-day submissions can fail and trigger late-deposit penalties. Watch for federal holidays that shift the semiweekly schedule.

Use each state's portal (NY PrompTax, CA EDD e-Services, IL MyTax, etc.) and any local lockbox or third-party processor (Berkheimer, RITA). Capture confirmation numbers in the workpaper for the audit trail.

Transmit through the payroll provider or MeF-approved software. 941 is due the last day of the month following quarter-end (Apr 30, Jul 31, Oct 31, Jan 31). Filings made via timely deposits in full receive a 10-day extension on the form itself, but the deposits themselves must still be on time.

Common rejection reasons: EIN mismatch, wrong tax period, prior-period overpayment carry-forward not reflected. Resolve and resubmit before the original deadline if at all possible to avoid a failure-to-file penalty layered on top of any tax due.

At Q4, the sum of the four 941s must tie to the W-3 totals for FIT, Social Security wages, and Medicare wages. SSA / IRS reconciliation notices (CP-2100, Notice 972CG) are triggered when these don't match — fix before W-2 transmittal, not after.

W-2s and the W-3 transmittal are due to employees and SSA by January 31 — the same deadline for both copies. Confirm box 12 codes (D for 401(k), DD for employer health, W for HSA) reconcile to the deduction registers.

Pull every vendor paid $600+ for services with a current W-9 on file. Exclude payments made via credit card or third-party processor — those are reported on 1099-K by the processor. Missing W-9s at year-end is a common cause of backup-withholding scramble.

Store the quarterly package in SmartVault / ShareFile per the firm's Written Information Security Plan. IRS requires payroll tax records for at least 4 years from the date the tax becomes due or is paid, whichever is later. Confirm encryption at rest and access logging are on.