The last estimated tax deadline of the year arrives right after the holidays, when many owners are busy closing books, running final payroll and planning for the new year. This Q4 estimated tax Union City guide explains what is due on January 15, 2027, how the federal and California rules differ, how safe-harbor amounts work, and a step-by-step checklist you can use before the payment window closes.
It is written for freelancers, consultants, sole proprietors, LLC members, S corporation owners and side-hustle earners in Union City and across the Tri-City area, including Fremont and Newark, as well as Hayward, San Leandro, Castro Valley and the wider Bay Area. If you had a strong fourth quarter, sold an asset or picked up new clients this fall, this is the payment that keeps a surprise penalty off your 2026 return.
What the Q4 Estimated Tax Payment Covers
The United States tax system is pay-as-you-go. Employees cover this through paycheck withholding, but if you are in business for yourself, the IRS says you generally need to make estimated tax payments. Those payments cover not only income tax, but also self-employment tax and alternative minimum tax, according to the IRS estimated taxes page.
For estimated tax purposes, the year is divided into four payment periods. The fourth period runs from September 1 through December 31, and its payment is due January 15 of the following year. For the 2026 tax year, the 2026 Form 1040-ES lists these federal due dates:
- 1st payment: April 15, 2026
- 2nd payment: June 15, 2026
- 3rd payment: September 15, 2026
- 4th payment: January 15, 2027
January 15, 2027 falls on a Friday, so there is no weekend shift this cycle. Keep in mind that a late or short payment can trigger a penalty even if you end up due a refund when you file.
Who Needs to Make Estimated Payments
Federal thresholds
The IRS says individuals, including sole proprietors, partners and S corporation shareholders, generally have to make estimated tax payments if they expect to owe tax of $1,000 or more when their return is filed. Corporations generally have to make estimated payments if they expect to owe $500 or more.
That covers a lot of local businesses. A Union City bookkeeper working as a sole proprietor, a Fremont software contractor paid on 1099s, a Hayward food truck owner and a San Leandro partner in a two-member LLC can all fall into the estimated tax system. S corporation owners often have wages with withholding, but distributions and other income can still leave a gap that estimated payments need to fill.
California thresholds
California runs its own estimated tax system through the Franchise Tax Board (FTB). According to the 2026 Form 540-ES instructions, you generally must make California estimated payments if you expect to owe at least $500 ($250 if married/RDP filing separately) for 2026 after subtracting withholding and credits, and you expect your withholding and credits to be less than the smaller of:
- 90% of the tax shown on your 2026 return, or
- 100% of the tax shown on your 2025 return, including alternative minimum tax.
Notice the difference: the federal individual threshold is $1,000, while the California individual threshold is $500. A Union City freelancer can be below one line and above the other, so check both.
Federal vs. California: Same Dates, Different Percentages
This is where many Bay Area owners get tripped up. The federal and California calendar due dates match, but the amounts required on each date do not.
On the federal side, the Form 1040-ES worksheet divides your required annual payment into four equal installments, one quarter each. California front-loads its schedule. The FTB 540-ES instructions set the required installments at:
- 1st installment (April 15, 2026): 30% of the required annual payment
- 2nd installment (June 15, 2026): 40%
- 3rd installment (September 15, 2026): 0%, no required payment
- 4th installment (January 15, 2027): 30%
So for a Union City owner, the January payment is roughly one quarter of the federal required annual payment and 30% of the California required annual payment. If you skipped the September California payment because none was required, that was correct, but it means January carries a meaningful share of your state estimate. When you work out your Q4 estimated tax Union City numbers, a simple spreadsheet with two columns, federal and California, keeps the math clear. More detail is on the FTB estimated tax payments page.
Safe Harbor Rules That Help You Avoid Penalties
Federal safe harbor
The IRS says most taxpayers avoid the underpayment penalty if they owe less than $1,000 in tax after subtracting withholding and credits, or if they paid at least 90% of the tax for the current year or 100% of the tax shown on the prior-year return, whichever is smaller.
Higher-income taxpayers have a stricter prior-year test. The 2026 Form 1040-ES explains that if your adjusted gross income for 2025 was more than $150,000 ($75,000 if your 2026 filing status is married filing separately), you substitute 110% for 100% in the prior-year test. Special rules apply to farmers and fishermen; if at least two-thirds of your gross income for 2025 or 2026 is from farming or fishing, the 90% figure becomes 66 2/3% and the 110% rule does not apply. IRS Publication 505 and Form 2210 cover these rules in detail.
California safe harbor
California has a similar structure with one important extra rule. Under the FTB 540-ES instructions, if your 2025 California AGI was more than $150,000 ($75,000 if married/RDP filing separately), you figure estimated tax based on the lesser of 90% of your 2026 tax or 110% of your 2025 tax, including AMT. This rule does not apply to farmers or fishermen.
The extra rule: if your 2026 California AGI is equal to or greater than $1,000,000 ($500,000 if married/RDP filing separately), you must figure estimated tax based on your 2026 tax. In other words, very high earners cannot rely on a prior-year percentage for California. If 2026 was a breakout year for your Union City business, or you sold a business interest or property, review the California side carefully before January.
Uneven income and annualizing
Many small businesses earn unevenly. A retailer or e-commerce seller may earn most of the year in November and December, while a contractor may land one large project in the fall. The IRS notes that if income is received unevenly, you may be able to avoid or lower the penalty by annualizing your income and making unequal payments, using Form 2210 with your return. The FTB 540-ES instructions also include an annualization option for California. This is worth reviewing with your preparer rather than guessing.
Filing Early Instead of Making the 4th Payment
Both the IRS and FTB give an alternative to the January payment, but the deadlines are different:
- Federal: You do not have to make the January 15, 2027 payment if you file your 2026 Form 1040 or 1040-SR by February 1, 2027 and pay the entire balance due with the return.
- California: If you file your 2026 California return by January 31, 2027 and pay the entire balance due, you do not have to make your last estimated payment and will not owe a penalty for the fourth installment.
This option works best for owners with simple books who already have their 1099s and year-end statements in hand. For most Union City small businesses with partnership K-1s, S corporation returns, payroll or inventory, the documents are not ready by late January, so making the Q4 payment is usually the practical route. Our tax preparation team can tell you quickly whether early filing is realistic for you.
How to Calculate Your Q4 Estimated Tax in Union City
A good Q4 estimated tax Union City calculation starts with clean books, not a guess. Use this order of operations:
- Close your books through November, then project December. Reconcile bank and credit card accounts and categorize every transaction. If your books are behind, our bookkeeping services can catch them up.
- Project full-year 2026 net profit for each business, including Schedule C income, partnership or S corporation income, and rental or investment income.
- Estimate self-employment tax on net earnings from self-employment, plus any other taxes the IRS lists, such as AMT.
- Subtract withholding and credits, including W-2 withholding from a spouse’s job or your own S corporation salary. Payroll set up through our payroll services can also be used to adjust withholding.
- Compare to your safe harbor: the smaller of 90% of 2026 tax or 100% (or 110%) of 2025 tax for federal, and the California equivalent, keeping in mind the $1,000,000 California AGI rule.
- Subtract what you already paid for April, June and September, plus any 2025 overpayment you applied to 2026.
- Calculate the federal and California January amounts separately, using one-quarter for federal and 30% for California, unless you annualize.
Year-end moves can change the math. Buying equipment, funding a retirement plan or timing invoices may lower your 2026 tax, so pair this calculation with year-end planning. Our Fremont small business year-end tax checklist and tax strategy and planning service walk through those decisions.
How to Pay: Federal and California Options
Paying the IRS
According to the IRS and the 2026 Form 1040-ES, you can pay through your IRS online account, IRS Direct Pay from a checking or savings account at no cost, debit or credit card or digital wallet (provider fees apply), the Electronic Federal Tax Payment System (EFTPS), or by mail with a Form 1040-ES voucher. Businesses can also make most common business tax payments, including estimated taxes, through their business tax account or Direct Pay for businesses. See IRS.gov/payments for the current options. Save the confirmation number for every payment.
If you mail a payment, the IRS treats the postmark date as the payment date, and the 2026 Form 1040-ES cautions that the postmark may reflect when the item is processed at a USPS facility rather than the day you drop it off. Paying electronically a few days early removes that risk.
Paying the FTB
California accepts estimated payments through Web Pay on the FTB website (you can schedule payments up to one year in advance), electronic funds withdrawal through tax software, or credit card. Watch the mandatory e-pay rule: once you make an estimate or extension payment exceeding $20,000, or file an original return with a total tax liability over $80,000, all later payments must be made electronically. Individuals who do not comply can face a 1% noncompliance penalty.
Q4 Estimated Tax Union City Checklist
Use this list between now and January 15, 2027:
- Pull your April, June and September 2026 payment confirmations for both IRS and FTB.
- Reconcile books through November and project December revenue and expenses.
- Confirm your 2025 federal AGI and 2025 California AGI to see whether the 110% prior-year rule applies.
- Check whether 2026 California AGI could reach $1,000,000 ($500,000 MFS), which removes the prior-year safe harbor for California.
- Figure the federal amount using one-quarter of the required annual payment, and the California amount using 30%.
- Decide whether early filing (federal by February 1, 2027; California by January 31, 2027) is realistic.
- Check whether California mandatory e-pay applies to you.
- Schedule payments electronically before the holidays so travel and office closures do not get in the way.
- Save confirmations in the same folder as your 2026 tax documents.
If you missed or underpaid an earlier installment this year, a larger January payment can reduce the penalty going forward, although it may not erase the penalty for earlier periods. If you have received an IRS notice, our IRS penalty abatement guide for Union City explains when relief may be available.
Common Mistakes Bay Area Business Owners Make
- Using the federal split for California. Paying one-quarter to the FTB in January when 30% is required can leave a California shortfall.
- Forgetting self-employment tax. Estimated tax covers more than income tax, and self-employment tax can be a significant share of the bill for new freelancers.
- Treating an extension as a payment extension. As we covered in our October 15 tax extension deadline guide, an extension gives more time to file, not more time to pay.
- Mixing business entity taxes with owner estimates. Personal 1040-ES and 540-ES payments are separate from entity-level obligations such as the California $800 franchise tax for LLCs and corporations.
- Waiting for the last day. Bank holds, login issues and holiday schedules can turn an on-time payment into a late one.
Q4 Estimated Tax Union City FAQs
When is the Q4 estimated tax payment due for the 2026 tax year?
For calendar-year individuals, the fourth federal estimated tax payment on Form 1040-ES covers income earned from September 1 through December 31, 2026 and is due January 15, 2027. The California fourth installment on Form 540-ES is also due January 15, 2027.
How much of my California estimated tax is due in January?
California does not split estimated tax evenly. Under the 2026 Form 540-ES instructions, the required installments are 30% in April, 40% in June, 0% in September and 30% in January. That means the January 15, 2027 payment is 30% of your required annual California payment, while the federal Form 1040-ES worksheet spreads the required annual payment over four equal installments.
Can I skip the January 15, 2027 payment by filing early?
Possibly. The IRS says you do not have to make the January 15, 2027 federal payment if you file your 2026 Form 1040 or 1040-SR by February 1, 2027 and pay the entire balance due with the return. California has a similar rule with an earlier date: if you file your 2026 California return by January 31, 2027 and pay the entire balance due, you do not have to make the last estimated payment and will not owe a penalty for the fourth installment.
Who has to make estimated tax payments?
Federally, individuals including sole proprietors, partners and S corporation shareholders generally must make estimated payments if they expect to owe $1,000 or more when they file, and corporations generally must if they expect to owe $500 or more. In California, individuals generally must make estimated payments if they expect to owe at least $500 ($250 if married/RDP filing separately) after withholding and credits, and withholding and credits will be less than the smaller of 90% of 2026 tax or 100% of 2025 tax including AMT.
What is the safe harbor for estimated tax penalties?
Federally, most taxpayers avoid the underpayment penalty if they owe less than $1,000 after withholding and credits, or if they paid at least 90% of current-year tax or 100% of prior-year tax, whichever is smaller. If 2025 AGI was more than $150,000 ($75,000 if married filing separately), the prior-year figure becomes 110%. California uses a similar 110% rule when 2025 California AGI is more than $150,000 ($75,000 if married/RDP filing separately), and taxpayers with 2026 California AGI of $1,000,000 or more ($500,000 if married/RDP filing separately) must base estimates on 2026 tax. Farmers and fishermen have special rules.
How do I pay federal and California estimated taxes online?
Federal payments can be made through your IRS online account, IRS Direct Pay, debit or credit card or digital wallet (provider fees apply), EFTPS, or electronic funds withdrawal when e-filing; see IRS.gov/payments. California payments can be made with FTB Web Pay, electronic funds withdrawal through tax software, or credit card. Once you make a California estimate or extension payment over $20,000, or file an original return with total tax liability over $80,000, all later California payments must be made electronically or a 1% noncompliance penalty can apply.
Get Help With Q4 Estimated Tax Union City Planning
Estimated taxes are easier when someone is watching both the federal and California numbers all year. Accountico helps freelancers, LLC owners, S corporation shareholders and growing businesses in Union City, Fremont, Hayward, Newark, San Leandro, Castro Valley and the Bay Area calculate accurate Q4 estimated tax payments, apply the right safe harbor and plan year-end moves before January 15, 2027.
Book a free 30-minute consultation or contact our team to review your numbers.
Accountico Inc
33476 Alvarado Niles Rd, Ste A007, Union City, CA 94587
(510) 400-9341
Disclaimer: This article is general information for small business owners and is not tax, legal or accounting advice. Tax rules change and individual situations differ. Confirm due dates and amounts with the IRS, the California Franchise Tax Board, or a qualified tax professional before acting.
