California Quarterly Estimated Taxes 2025 | Evin Wick
- Evin Wick
- Jul 3
- 4 min read
Updated: Jul 22
Table of Contents
What Are Quarterly Estimated Taxes?
If you earn income without paycheck withholding—think 1099 consulting, LLC profits, or rental cash flow—the IRS and California Franchise Tax Board (FTB) expect you to pre-pay tax in four installments. You’re in the clear when you’ve prepaid 100 % of last year’s combined tax bill (110 % if your 2024 federal AGI topped $150 k) or 90 % of this year’s eventual bill.
California Quarterly Tax Estimates: Two Simple Ways to Estimate
IRS guidance for Estimated taxes
Last-Year “Safe Harbor” (fast & easy)
Federal quarterly = 2024 total federal tax ÷ 4
California quarterly = 2024 total CA tax ÷ 4
Bump the federal figure by 10 % before dividing if your 2024 AGI was over $150 k; California has no bump.
Current-Year Projection (Detailed Walk-Through)
Step | What to do | Why it matters |
1. Combine projected 2025 income | Net business profit + any wages, interest, dividends, rental income, etc. MFJ? Include your spouse’s W-2 wages and note the federal tax already withheld. | Creates a full-household starting point. |
2. Subtract deductions | • Standard deduction 2025: $15,000 single / $30,000 MFJ • OR your expected itemized total (mortgage interest, property tax, charitable gifts, etc.). | Lowers your taxable income. |
3. Apply the SE-tax haircut | Net SE earnings = Net business profit × 0.9235 | The IRS makes you pay SE-tax only on 92.35 % of profit. |
3. Apply the Qualified Business Income Deduction | This is your business income x .20. | The IRS provides a deduction for small business income. |
4. Look up your income-tax bill (cheat sheet) | — Single Filers — • $48,476 – $103,350 → $5,578.50 + 22 % of amount over $48,475 • $103,351 – $197,300 → $17,651 + 24 % of amount over $103,350 — Married Filing Jointly — • $96,951 – $206,700 → $11,157 + 22 % of amount over $96,950 • $206,701 – $394,600 → $35,302 + 24 % of amount over $206,700 | Gives you the bulk of your federal bill. |
5. Add self-employment tax | SE tax = Net SE earnings × 15.3 % | Covers Social Security & Medicare. |
6. Total federal tax | Income-tax (Step 4) + SE-tax (Step 5) | — |
7. Account for spouse withholding (MFJ) | Subtract whatever federal tax is already coming out of your spouse’s paychecks. | Keeps you from double-paying. |
8. Divide by 4 | That amount is your federal quarterly payment. | Voilà! |
Step | What to do | Why it matters |
1. Start with federal taxable income | Then subtract CA’s standard deduction ($5,540 single / $11,080 MFJ) or your estimated CA itemized amount. | Aligns with state rules. |
2. Use the CA bracket shortcut | Single (double thresholds for MFJ) • $40,246 – $55,866 → $992.26 + 6 % of amount over $40,245 • $55,867 – $70,606 → $1,929.52 + 8 % of amount over $55,866 • $70,607 – $360,659 → $3,108.72 + 9.3 % of amount over $70,606 | Yields your CA income-tax. |
3. Divide by 4 | That amount is your California quarterly payment. | — |
Pro tip: Round each installment up to the nearest $10–$100 to stay safely within IRS/FTB 90 % safe-harbor.
2025 Due Dates (Why June Isn’t July)
Quarter | IRS & FTB Deadline | Notes |
Q1 | April 15, 2025 | Standard Tax Day |
Q2 | June 16, 2025 * | Due two weeks before the quarter ends (June 15 falls on Sunday) |
Q3 | September 15, 2025 | Normal 15th |
Q4 | January 15, 2026 | Final installment next January |
* When the 15th falls on a weekend/holiday, you get the next business day.
What Happens If You Don’t Pay? Interest vs. Penalties
Federal (IRS) | California (FTB) | |
Interest on unpaid tax | 7 % / yr, compounded daily for Q3 2025 | 8 % Jan–Jun 2025; 7 % Jul–Dec 2025 |
Late-payment penalty | 0.5 % of unpaid tax per month (max 25 %) | 5 % up front + 0.5 %/mo (max 25 %) |
Cost vs. market | Combined annualized cost ≈ 13 %—higher than July 2025 prime rate of 7.50 % |
Interest starts the day your payment is late; penalties kick in once you miss the required quarterly amount.
How & Where to File
Online (fastest)
Agency | Free bank draft | Other choices |
IRS | Direct Pay / EFTPS | Debit/credit card, IRS2Go |
FTB | Web Pay | Card, installment plan |
By Mail (check + voucher)
Tear off your voucher: Form 1040-ES (federal) or Form 540-ES (California).
Write a check payable to “United States Treasury” or “Franchise Tax Board.”
Mail with a tracked service to the correct address:
Agency | Mailing address |
IRS (CA filers) | Internal Revenue Service P.O. Box 802502 Cincinnati, OH 45280-2502 |
FTB | Franchise Tax Board P.O. Box 942867 Sacramento, CA 94267-0008 |
In the memo line, note your SSN/EIN and the form year (e.g. “2025 Form 1040-ES”).
Wrap-Up
Quarterly estimates aren’t optional, especially in California, where state + federal interest and penalties outpace most loans if you fall behind. Use the two methods above, note the four quirky 2025 deadlines (June 16!), and file online or by mail.
Hate the math? S Works monitors your income in real time, auto-calculates each installment, and submits both IRS and FTB payments for you, so you can focus on growing your business instead of juggling due dates.
Ready for painless quarterly taxes? Schedule a call with us.
Evin Wick JD, LLM is a Georgetown-trained tax lawyer and co-founder of S-Works, where he channels two decades of small-business tax expertise into streamlined S-Corp, bookkeeping, and payroll solutions for solo consultants.
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