Connecticut Withholding Tax Requirements for Employers: CT-W4 and CT-941

Connecticut withholding tax requirements for employers come down to five duties: register with the Department of Revenue Services (DRS), collect a Form CT-W4 from every employee, calculate the right amount using the state’s withholding tables or Circular CT, deposit the tax electronically through myconneCT on your assigned schedule, and reconcile the totals quarterly on Form CT-941 and annually on Form CT-W3. Rates run from 2% to 6.99% depending on wages and filing status, and nearly everything moves through myconneCT.¹

Registering With DRS

Any business that maintains an office or does business in Connecticut and is an employer for federal withholding purposes must register for state withholding, even if payroll is handled from out of state.² Registration happens through myconneCT. If you’re already registered with DRS for another tax such as sales and use, you can add withholding as an additional liability through the same account.

Registration produces a Connecticut Tax Registration Number. It’s not the same as your federal EIN, and it’s not the number the Department of Labor issues. The DRS number has to appear on every withholding form and every piece of correspondence you send to DRS.¹

Form CT-W4 for Every Employee

Each employee has to complete Form CT-W4, the Connecticut Employee’s Withholding Certificate, which gives you the filing status and any adjustments. The obligation to withhold begins with the first wage payment to an employee performing services in the state.³

Don’t guess if a CT-W4 never comes back. When an employee hasn’t turned in a completed form, Connecticut requires you to withhold at the top marginal rate of 6.99% with no exemption applied.³ Watch for anything the employee adds on Line 2 (additional withholding requested) or Line 3 (reduced withholding), and apply those too.

Calculating the Right Amount

Connecticut does not offer a flat-rate shortcut for regular wages. You use either the wage bracket tables or the calculation rules in Circular CT, the state’s Employer’s Tax Guide.³ The calculation runs in five steps:

Annualize the wages by multiplying the pay-period gross by the number of pay periods in the year.
Subtract the personal exemption, which depends on filing status and wage level from the CT-W4.
Apply the seven progressive brackets, starting at 2% and climbing to 6.99% above the top threshold. Bracket widths differ by filing status code; Code C (married filing jointly) has wider brackets than Code F (single).
Apply any phase-out add-backs or credits. Higher earners face a phase-out of the personal exemption that raises the effective tax.
Divide the annual tax by the number of pay periods to get the per-paycheck amount.

The calculation can never produce a negative number. If the math falls below zero after adjustments, withholding for that pay period is zero. Use the current year’s Circular CT; tables and exemption amounts move with new legislation.

Bonuses, Commissions, and Other Supplemental Pay

Supplemental compensation is where employers most often slip. Unlike the federal rules, Connecticut has no flat percentage option for supplemental wages.³ If the bonus or commission is paid with the regular paycheck, add it to the regular wages and withhold on the combined amount. If it’s paid separately, compute the tax on the combined regular and supplemental wages, then subtract the tax already withheld from the regular wages; the remainder is the supplemental withholding. If no tax was withheld from regular wages, combine both and withhold on the full amount.

Depositing the Tax

How often you remit depends on how much withholding you reported during a 12-month look-back period. There are three tiers:³

Weekly remitter (more than $10,000 in the look-back period): payment due the Wednesday following the weekly pay period.
Monthly remitter (more than $2,000 but not more than $10,000): payment due by the 15th of the month after wages were paid.
Quarterly remitter ($2,000 or less): payment due by the last day of the month after quarter-end.

Every payment goes through myconneCT by electronic funds transfer. Paper checks are not accepted unless DRS has granted a specific waiver, which you request on Form DRS-EWVR.¹ Weekly and monthly remitters generally pair their payments with Form CT-WH.

Quarterly and Annual Reconciliation

Form CT-941

Every registered employer files Form CT-941, the Quarterly Reconciliation of Withholding, even in quarters when no wages were paid and no tax was withheld. A seasonal employer that temporarily stops paying wages still files rather than closing out.⁴ Deadlines:

Q1 (January–March): April 30
Q2 (April–June): July 31
Q3 (July–September): October 31
Q4 (October–December): January 31

The CT-941 is filed electronically through myconneCT. If the amount withheld differs from what was already deposited, you either owe a final payment or carry a credit forward. Employers who made timely deposits covering the full quarter’s tax may have an additional ten days beyond the standard deadline to file.⁴ To correct a filed CT-941, use Form CT-941X.

Form CT-W3 and W-2s

By January 31 of the following year, every employer files Form CT-W3, the Annual Reconciliation of Withholding, together with the state copies of all federal W-2s issued to employees.⁵ The CT-W3 totals must match the W-2 totals exactly. Electronic submission applies regardless of how many employees you have.

Non-Resident Employees and Remote Workers

Withholding on wages paid to non-residents applies only to services actually performed in Connecticut. A non-resident employee working entirely outside the state is not subject to Connecticut withholding, even if your headquarters or payroll office is in Connecticut.¹ For employees who split their time between Connecticut and another state, you apportion the withholding to reflect the share of wages tied to Connecticut work. Form CT-W4NA, the Employee’s Withholding Certificate for Nonresident Apportionment, helps with that calculation.

Connecticut has no reciprocal agreements with other states, so you cannot skip Connecticut withholding on a non-resident just because the home state also has an income tax.⁶ A New York or Massachusetts resident earning Connecticut-sourced wages still has Connecticut tax withheld.

Connecticut applies a “convenience of the employer” rule on a reciprocal basis only. It treats a non-resident working remotely for a Connecticut employer as if the work were performed in Connecticut, but only when the employee’s home state applies its own version of the rule. In practice this chiefly affects non-residents living in New York. If the employee’s home state has no convenience rule, Connecticut doesn’t impose one.⁷

Penalties, Interest, and Personal Liability

A late payment or underpayment of withholding tax carries a penalty of 10% of the amount due. If no tax is owed but a return is filed late, DRS can assess a $50 penalty. Interest accrues on any balance at 1% per month (or fraction of a month) from the original due date until paid.⁸

Because electronic filing and payment are mandatory, filing on paper without a waiver triggers a separate graduated penalty:⁸

First offense: 10% of the required payment, capped at $2,500.
Second offense: 10% of the required payment, capped at $10,000.
Third and later offenses: 10% with no cap.

Withheld income taxes are trust fund taxes in Connecticut. If the business fails to remit them, DRS can look past the entity. Under Conn. Gen. Stat. § 12-736, any person with the duty and authority to collect, account for, or pay over the tax can be held personally liable for the full amount. That reaches corporate officers, directors, shareholders with authority over funds, partners, LLC members, and payroll service providers.⁹ The responsible-person penalty can equal the entire unpaid tax.

Recordkeeping

Keep accurate payroll and withholding records at the place of employment for at least three years for each employee. The file should include each CT-W4, documentation supporting the withholding calculation for every pay period, deposit confirmations from myconneCT, and filed copies of every CT-941 and CT-W3. Clean records are the strongest defense if DRS questions your deposits or issues an assessment.

Closing or Selling the Business

An employer that goes out of business or permanently stops paying wages must notify DRS right away by filing a final CT-941 for the current quarter through myconneCT, filing Form CT-W3, issuing W-2s to all employees, and submitting the W-2 copies to DRS.¹⁰ A business that had employees also needs to cancel its registration with the Connecticut Department of Labor.

If you’re selling, the buyer inherits withholding tax exposure. When the seller has unpaid withholding tax, the buyer must hold back enough of the purchase price to cover the taxes, interest, and penalties until the seller produces a DRS receipt showing a clear balance. A buyer who fails to hold back the required amount becomes personally liable for the unpaid taxes up to the purchase price.¹¹

1
Connecticut State Department of Revenue Services. 2026 – Withholding Tax Information
2
Connecticut State Department of Revenue Services. New Employer Information
3
Connecticut Department of Revenue Services. IP 2026(1) – Connecticut Employer’s Tax Guide
4
Legal Information Institute. Conn. Agencies Regs. 12-707-1 – Schedule for Filing Withholding Tax Returns and Payment of Taxes
5
Connecticut Department of Revenue Services. DRS 2026 Tax Filing Due Dates Calendar
6
Connecticut General Assembly. State Income Taxes on Income Sourced to Other Jurisdictions
7
Connecticut General Assembly. Convenience of the Employer Rule
8
Connecticut State Department of Revenue Services. Other Helpful Information
9
Connecticut Department of Revenue Services. Can I Be Held Personally Liable For Payment of Business Taxes
10
Connecticut State Department of Revenue Services. Other Helpful Information
11
Justia Law. Connecticut Code Title 12 – Section 12-707