NJ Q3 2026 Estimated Tax Payments: September 15 Deadline, Forms, and Safe Harbors Explained

Third-quarter 2026 estimated tax payments are due Tuesday, September 15, 2026. One date covers federal Form 1040-ES, NJ-1040-ES, NJ BAIT (PTE-150), and NJ CBT-150 installments. The same date is also the extended filing deadline for calendar-year Form 1120-S and Form 1065 returns. This guide covers who pays, which form to use, and the safe-harbor math that avoids underpayment penalties.

The Q3 federal installment covers income earned June 1 through August 31, 2026, per the payment-period table in the IRS Form 1040-ES instructions. If your withholding will not cover at least 90% of your 2026 tax (or 100%/110% of 2025’s), you generally owe this installment.

Planning information only — not tax advice. Last reviewed against IRS.gov primary sources on 2026-07-23. See Disclaimer.

Who Owes Q3 2026 Estimated Tax Payments

Federal Form 1040-ES payments are required if you expect to owe at least $1,000 in 2026 federal tax after withholding and refundable credits, per the IRS Form 1040-ES instructions.

In New Jersey, individuals owe NJ-1040-ES estimates when expected NJ tax exceeds $400, per NJ Division of Taxation guidance. NJ pass-through entities that elected BAIT for 2026 owe quarterly PTE estimated payments. NJ C-corporations owe CBT-150 installments.

NJ owners who typically owe a Q3 estimate:

• Self-employed sole proprietors (Schedule C)
• S-corp owners (W-2 wages do not cover the K-1 distribution income)
• Partnership and multi-member LLC partners (K-1 income)
• Rental real estate owners with positive net income
• High-income W-2 earners with large investment, RSU, or side income
• BAIT-electing pass-through entities (PTE-150)
• NJ C-corporations (CBT-150)

Federal Form 1040-ES: 2026 Third-Quarter Installment

The IRS Third Quarter Tax Calendar confirms the date: “Individuals: Pay the third installment of your 2026 estimated tax — Use Form 1040-ES.”

September 15, 2026 falls on a Tuesday, so no weekend or holiday shift applies. All four 2026 federal individual estimated tax installments:

• Q1 2026: April 15, 2026 (passed)
• Q2 2026: June 15, 2026 (passed)
• Q3 2026: September 15, 2026 — covers June 1 through August 31 income
• Q4 2026: January 15, 2027 — covers September 1 through December 31 income

Federal Safe Harbor Methods

To avoid the IRS underpayment penalty, total payments plus withholding must satisfy one safe harbor. Per the IRS Form 1040-ES instructions, you generally avoid the penalty by paying at least:

• 90% of your current-year (2026) total tax liability, OR
• 100% of your prior-year (2025) total tax — if your 2025 adjusted gross income was $150,000 or less ($75,000 or less if married filing separately), OR
• 110% of your prior-year (2025) total tax — if your 2025 AGI exceeded $150,000 ($75,000 if married filing separately)

For higher-income NJ taxpayers, the 110% prior-year anchor is the simplest. Multiply 2025 total tax by 110%. Subtract withholding plus the Q1 and Q2 payments already made. Then split the remainder across Q3 and Q4.

ProAxis’s free Federal Estimated Tax Calculator runs the federal 90% / 100% / 110% safe-harbor math. It then splits the result into 2026 quarterly installments.

How to Pay the Federal Q3 Installment

Three approved methods, each documented at IRS.gov:

• IRS Direct Pay: free bank transfer at IRS Direct Pay
• EFTPS: the Electronic Federal Tax Payment System — used by most businesses and high-volume payers
• Form 1040-ES voucher by mail with check or money order

Submit IRS Direct Pay payments by 8 p.m. Eastern time on September 15. The IRS treats a same-day payment submitted after 8 p.m. ET as made the next business day. EFTPS payments must be scheduled at least one business day ahead. Check the current EFTPS cutoff before relying on a September 15 submission. Mailed Form 1040-ES vouchers must be postmarked by September 15. Bank holidays do not extend the deadline. Source: IRS, Direct Pay help; EFTPS.gov.

NJ-1040-ES Individual Estimated Tax: Same Deadline

NJ residents and non-residents with NJ-source income use Form NJ-1040-ES for state estimates. The NJ Q3 deadline matches the federal: September 15, 2026. NJ offers online payment through the NJ Division of Taxation portal; mailed vouchers must be postmarked by September 15.

NJ Safe Harbor

NJ’s safe harbor is not the federal one. New Jersey has no 110% tier and no $150,000 income condition. Estimated payments plus withholding must total at least the lesser of these two figures:

• 80% of the current-year NJ tax liability, OR
• 100% of the prior-year NJ tax liability — available at every income level, including taxpayers whose prior-year NJ Gross Income exceeded $150,000. The prior-year return must have covered a full 12 months and shown a tax liability.
• Federal contrast: the 110% prior-year rule is federal only, for taxpayers whose prior-year AGI exceeded $150,000. New Jersey has no matching tier. Form NJ-2210 lists four exceptions, and none is based on NJ Gross Income. (Source: NJ Division of Taxation, GIT-8, January 2026.)

Multi-state owners should model the credit for taxes paid to other jurisdictions before setting the estimate. NJ taxes residents on worldwide income and non-residents on NJ-source income only. A CPA can model the correct number.

NJ BAIT Q3 Estimated Payment (PTE-150) — Same September 15 Deadline

Pass-through entities that elected BAIT for the 2026 tax year owe a Q3 estimated payment on September 15, 2026. The payment is made on Form PTE-150. Per the NJ Division of Taxation PTE/BAIT FAQ, the four calendar-year BAIT installments are April 15, June 15, September 15, and January 15.

A Q3 true-up matters more than the earlier quarters. By September the entity has eight months of actual distributive proceeds on the books. Comparing YTD actuals against a flat 25%-per-quarter estimate catches shortfalls before Q4.

A late BAIT payment costs the entity underpayment interest. Worse, insufficient payments can push the federal deduction into the wrong year. That undermines the SALT-cap-workaround logic that drives the election. ProAxis covers strategy in depth on the NJ BAIT Election service page.

NJ CBT-150 Corporate Estimated Tax — Same Deadline

Calendar-year NJ C-corporations owe a Q3 CBT-150 installment on September 15, 2026. The IRS calendar carries the parallel federal entry: “Corporations: Deposit the third installment of your 2026 estimated tax.”

Corporations whose prior-year CBT liability is greater than $1,500 must make installment payments. The schedule is 25% in the 4th, 6th, 9th, and 12th months of the accounting period. Corporations with $50 million or more in prior-period gross receipts follow a different schedule. They pay 25% in the 4th month, 50% in the 6th, and 25% in the 12th. (2026 Form CBT-150 instructions; 2025 CBT-100 instructions, Line 7.)

Multi-state corporations should run the NJ apportionment formula before paying. Allocation factors and combined-reporting rules change the installment math.

Two September 15 Deadlines: Extended 1120-S and 1065 Returns

September 15, 2026 is not just an estimated tax date. It is also the extended filing deadline for calendar-year pass-through returns. Per the IRS Third Quarter Tax Calendar:

• Form 1120-S (S-corporations): “File calendar year Form 1120S if you timely requested a 6-month extension.”
• Form 1065 (partnerships): “File calendar year Form 1065 if you timely requested a 6-month extension.”

The original March 2026 due date moved to September 15 for entities that filed Form 7004 on time. There is no second extension. A late 1120-S or 1065 triggers a late-filing penalty that multiplies by owner count and by month.

For owners this creates a stacked deadline. The entity’s extended return and the owner’s Q3 estimate land on the same day. K-1s finalized in September often move the owner’s personal numbers. Re-run the safe-harbor math once the final K-1 figures are in, then pay the Q3 installment the same week. First-year S-corp owners can map the full filing chain in our first-year S-Corp compliance checklist.

Missed Q2? The Catch-Up Math

A missed June 15 installment does not wait for a penalty notice. The federal underpayment penalty accrues from June 15 until the shortfall is paid, calculated on Form 2210. The IRS rate for individual underpayments is 7% for Q3 2026, after 6% in Q2 2026 and 7% in Q1 2026, per the IRS quarterly interest rates page.

The catch-up sequence:

• Pay the Q2 shortfall now. Accrual stops on the paid amount the day it posts.
• Pay Q3 on time and in full. Catching up does not erase the Q2 penalty, but it stops new quarters from stacking.
• Re-run the safe harbor against YTD actuals. If income arrived unevenly, the annualized income method on Form 2210 may lower the required earlier-quarter installments.

NJ underpayment charges run on a similar quarter-by-quarter mechanic via Form NJ-2210. The full Q2 mechanics — forms, NJ treatment, and payment methods — are in our Q2 2026 estimated tax guide. Every 2026 federal and NJ deadline is listed on our 2026 tax calendar.

Q3 2026 Estimated Tax — Frequently Asked Questions

Who must pay Q3 2026 estimated taxes?

The Q3 2026 federal estimated tax installment is due September 15, 2026 on Form 1040-ES. You generally owe it if you expect at least $1,000 of 2026 federal tax after withholding and refundable credits. In New Jersey, NJ-1040-ES estimates apply when expected NJ tax exceeds $400. Typical payers: self-employed owners, S-corp shareholders with K-1 income, partners, landlords with net rental income, BAIT-electing entities (PTE-150), and NJ C-corporations (CBT-150).

What if I missed the Q2 estimated payment on June 15?

Pay the Q2 shortfall as soon as possible. The federal underpayment penalty accrues from June 15, 2026 until the shortfall is paid. The IRS individual underpayment rate is 7% for Q3 2026 (July through September). Paying now stops new accrual but does not erase the penalty already built up. Then pay the Q3 installment in full on September 15, 2026 so a second underpaid quarter does not stack on top.

When is the NJ BAIT Q3 estimated payment due?

The NJ BAIT (Business Alternative Income Tax) Q3 estimated payment is due September 15, 2026 for calendar-year pass-through entities. The payment is made on Form PTE-150. All four BAIT installments for calendar-year entities follow the same schedule as federal estimates. They are due April 15, June 15, September 15, and January 15 of the following year.

Are extended S-corp and partnership returns also due September 15, 2026?

Yes. Per the IRS Third Quarter Tax Calendar, extended calendar-year Form 1120-S and Form 1065 returns are due September 15, 2026. This applies to returns on a timely six-month extension (Form 7004). There is no second extension. The same date carries the Q3 estimated tax installment, so S-corp and partnership owners often face both deadlines in the same week.

How do I calculate my Q3 payment if my income jumped mid-year?

Recompute the safe harbor against actual year-to-date income. One approach: pay enough with Q3 to bring total payments to three of the four equal installments of the annual safe-harbor amount. The other: use the annualized income installment method on Form 2210, which matches each installment to income actually earned in that period. A mid-year jump — a large capital gain, RSU vesting, or a strong business quarter — usually makes the annualized method worth running.

Sources and Primary Materials

This guide cites primary government materials only:

• IRS — Third Quarter Tax Calendar (9/15/2026 deadlines)
• IRS — Quarterly Interest Rates
• IRS — Estimated Taxes (Small Businesses & Self-Employed)
• IRS — Estimated Tax FAQ
• IRS — Form 1040-ES (2026)
• IRS — Direct Pay
• EFTPS — Electronic Federal Tax Payment System
• NJ Division of Taxation — PTE/BAIT FAQ (Q3 9/15 deadline)
• NJ Division of Taxation — Main Site

Federal dates, extended-return deadlines, and interest rates were verified against IRS.gov on 2026-07-23. NJ figures carry forward from the primary-source verification of 2026-07-16.

How ProAxis Helps with Q3 Estimated Tax Planning

ProAxis Tax & Accounting Services is a licensed CPA firm based in Hasbrouck Heights, Bergen County NJ. We are licensed in NJ and NY, AICPA members, and Authorized IRS e-File Providers. Practice focuses on small and mid-size businesses across the NYC Metro Tri-State area.

For Q3 estimated tax planning specifically, we work with NJ owners on:

• Federal and NJ safe-harbor calculations under engagement
• BAIT PTE-150 estimated payment modeling and Q3 true-ups for pass-through entities
• CBT-150 calculation for NJ C-corporations
• Extended 1120-S and 1065 filing coordinated with the owner’s Q3 estimate
• Annualized income installment calculations when income varies by quarter

For planning under engagement, schedule a discovery call through the contact page or call 201-800-2330.

General information only — not tax advice. Every business situation is different. The dates and rules cited above are accurate to primary government sources as of 2026-07-23 but are subject to subsequent IRS or NJ Division of Taxation guidance. No CPA-client relationship is created by reading this article. See Disclaimer and Terms of Service for the full terms.