By David Nguyen, CPA – Accounting Fresh CPA Inc. | Carlsbad, CA
If you’re a business owner in Carlsbad, Oceanside, Vista, Encinitas, or anywhere in San Diego County, quarterly estimated taxes are something you cannot ignore.
Whether you run a construction company, plumbing business, real estate firm, marketing agency, or service-based company, understanding estimated taxes will help you:
- Avoid IRS and California penalties
- Protect your cash flow
- Stay compliant year-round
- Reduce stress at tax time
At Accounting Fresh CPA Inc., we help California business owners proactively plan their tax payments — not scramble in April.
If you’re searching for the best business accountant and bookkeeper in Carlsbad or San Diego, this guide is for you.
What Are Quarterly Estimated Taxes?
Quarterly estimated taxes are payments made throughout the year to the:
- Internal Revenue Service (Federal)
- California Franchise Tax Board (California)
Instead of paying all your taxes on April 15, the government requires business owners to prepay taxes as income is earned.
If you expect to owe:
- $1,000+ to the IRS, or
- $500+ to California
You generally must make quarterly payments.
Who Needs to Pay Estimated Taxes?
In California, quarterly payments usually apply to:
- Sole proprietors (Schedule C filers)
- S-Corp shareholders
- Partnership owners
- LLC members
- Independent contractors (1099 income)
- Real estate investors
- Consultants and service-based business owners
If you own an S-Corp and take distributions beyond payroll, you may still owe quarterly taxes personally.
2026 Estimated Tax Due Dates
For both federal and California taxes:
- April 15
- June 15
- September 15
- January 15 (following year)
⚠️ California has a unique rule:
- 30% due in April
- 40% due in June
- 0% in September
- 30% in January
This catches many business owners off guard.
How Are Estimated Taxes Calculated?
Estimated taxes are based on:
- Projected net profit
- Other income (W-2, investments, spouse income)
- Self-employment tax
- Qualified Business Income (QBI) deduction
- State tax impact
- Prior year safe harbor rules
Safe Harbor Rule
To avoid penalties, you can generally pay:
- 100% of last year’s tax (110% if high income), OR
- 90% of current year tax
For high-earning California business owners (very common in San Diego), this calculation becomes critical.
Why Many Business Owners Overpay (or Underpay)
We often see business owners:
- Guess their quarterly payments
- Use outdated profit numbers
- Ignore California allocation rules
- Forget about payroll vs distributions (S-Corps)
- Not adjust after a big contract or revenue spike
Without accurate bookkeeping, quarterly tax planning is just guessing.
And guessing leads to penalties.
The Link Between Bookkeeping and Estimated Taxes
You cannot calculate accurate estimated taxes without clean books.
If your:
- Bank accounts aren’t reconciled
- Credit cards are uncategorized
- Profit & Loss isn’t accurate
- Owner distributions are messy
Your tax estimate will be wrong.
This is why we position ourselves as both:
✔️ Business Accountant
✔️ Bookkeeper
✔️ Strategic Tax Advisor
If you’re searching for the best business accountant and bookkeeper in Carlsbad, that combination matters.
California-Specific Considerations
California business owners face additional complexity:
- $800 minimum franchise tax for LLCs
- Gross receipts fees for LLCs
- S-Corp 1.5% CA entity tax
- High personal income tax brackets
- PTET (Pass-Through Entity Tax) elections
Missing one of these items can significantly impact your quarterly estimate.
Example: San Diego Construction Business Owner
Let’s say a Carlsbad contractor earns:
- $300,000 net business income
- Pays themselves $80,000 W-2 salary (S-Corp)
- Takes $150,000 in distributions
Without planning, they could:
- Underpay federal tax
- Underpay California tax
- Miss PTET opportunity
- Face 5-figure penalties
With proactive quarterly planning, we structure:
- Proper payroll
- Smart distributions
- Optimized estimated payments
- Cash flow protection
How We Help California Business Owners
At Accounting Fresh CPA Inc., our quarterly tax process includes:
- Monthly bookkeeping & reconciliation
- Real-time financial reporting
- Quarterly tax projection updates
- Safe harbor calculations
- California tax optimization
- PTET analysis
- Cash flow planning
We don’t just file returns — we help you plan proactively.
Searching for the Best Business Accountant and Bookkeeper in Carlsbad?
If you’re a small business owner in:
- Carlsbad
- Oceanside
- Vista
- Encinitas
- San Marcos
- North County San Diego
And you want:
- Clean books
- Accurate quarterly estimates
- Proactive tax planning
- Clear financial visibility
We’re here to help.
Final Thoughts
Quarterly estimated taxes are not just compliance.
They are a cash flow strategy.
Handled correctly, they:
- Reduce stress
- Prevent penalties
- Optimize tax savings
- Improve decision-making
Handled incorrectly, they create chaos.
If you want support from a local Carlsbad CPA firm that specializes in bookkeeping, tax planning, and strategic advisory, let’s talk.
📍 Accounting Fresh CPA Inc.
Carlsbad, California
Serving San Diego County small businesses
👉 Schedule a consultation today and let’s build a proactive tax plan for 2026.