FAQ’s

The federal filing deadlines for a calendar-year business are generally:

Entity Type Return Due Date

Sole Proprietorship / Single-Member LLC (default tax treatment) Form 1040 + Schedule C April 15

Partnership / Multi-Member LLC (default tax treatment) Form 1065 March 15 (or next business day)

S Corporation Form 1120-S March 15 (or next business day)

C Corporation Form 1120 April 15

For the current filing season (2025 returns filed in 2026), those dates fall as follows:

• Partnerships and S Corporations: March 16, 2026 (because March 15 is a Sunday)
• Individuals, sole proprietors, and most C Corporations: April 15, 2026

⚠ Extensions are available, but they generally extend the filing deadline, not the payment deadline. Taxes owed are still due by the original due date.

In California, your sales tax return is usually due one month after the end of the reporting period.

If you file quarterly (most common for small businesses)

• Jan–Mar → Due April 30
• Apr–Jun → Due July 31
• Jul–Sep → Due October 31
• Oct–Dec → Due January 31

If you file monthly
Each month’s return is due on the last day of the following month.

• January sales → Due February 28/29
• February sales → Due March 31
• March sales → Due April 30
• And so on.

If you file annually

The entire year’s return is due January 31 of the following year.

ℹ Your filing frequency (monthly, quarterly, or annual) is assigned by the California Department of Tax and Fee Administration and can be found in your CDTFA online account.

For most small California businesses, the key dates to remember are:

April 30
July 31
October 31
January 31

Here are some of the most common ways business owners reduce taxes before year-end:

Buy needed business items before December 31

• Equipment
• Computers
• Software
• Office supplies
• Marketing services

Contribute to a retirement plan

• Solo 401(k)
• SEP IRA
• SIMPLE IRA

Track and claim all business expenses

• Vehicle mileage
• Home office (if eligible)
• Travel
• Professional fees
• Insurance

Other strategies

• Delay income when possible — if you’re a cash-basis business, consider collecting some payments in January instead of December.
• Pay employee bonuses before year-end — may increase your current-year deduction.
• Maximize HSA contributions — if you’re eligible for a Health Savings Account.
• Review investments — capital losses may offset capital gains.

★ The most important step: Meet with your advisor before year-end and run a tax projection. This helps identify opportunities while there’s still time to act.

You may have the wrong entity structure if your business is making good money and you’re paying more tax than you think you should.

Ask yourself

• What is my business profit each year?
• Am I the only owner?
• Do I have employees?
• Am I currently a sole proprietor, LLC, S Corp, or C Corp?

Common guideline

• Low to moderate profit: A sole proprietorship or LLC is often sufficient.
• Higher profit: An S Corp may save money on self-employment taxes.
• Outside investors or plans to retain significant earnings: A C Corp may be worth considering.

When to review your entity structure

• Your profit has increased significantly.
• Your business has changed (employees, partners, new locations, etc.).
• You haven’t reviewed your structure in several years.

💡Once a year, ask your tax advisor: “If I were starting this business today, would I choose the same entity structure?” If the answer is no, there may be tax savings available by changing your tax classification or business structure.

For most businesses and individuals in the U.S., federal estimated tax payments are due on:

Payment Due Date

1st Quarter April 15

2nd Quarter June 15

3rd Quarter September 15

4th Quarter January 15 of the following year

If a due date falls on a weekend or federal holiday, it moves to the next business day.

Who typically needs to make estimated payments?

• Sole proprietors
• Single-member LLC owners
• Partners in partnerships
• S Corp owners who don’t have enough tax withheld from wages
• Anyone expecting to owe a significant amount of tax when filing

California estimated tax dates

California generally uses the same schedule, but requires uneven payment percentages (30%, 40%, 0%, 30%) unless you use an approved annualized income method.

April 15
June 15
September 15
January 15

📅 If you’re self-employed or own a business and taxes aren’t being withheld from your income, put these dates on your calendar. Those are the key quarterly estimated tax deadlines for both federal and California taxes.