Owner tax planning guide
The Busy Owner's DIY Tax Planning Guide
Stop reacting to tax bills. Learn how to set your S-corp salary correctly, calculate your quarterly estimates, and build a proactive plan that eliminates April surprises.
Why reactive filing costs you
Most profitable business owners pay more in taxes than they should — not because their CPA makes mistakes, but because the conversation happens in March instead of October. By the time you’re signing your return, the planning window has closed.
Reactive filing means you’re writing checks instead of making decisions. Proactive planning means you understand what you owe before you owe it, and you have time to do something about it.
The core problem
This guide covers the three levers that matter most for a profitable service business: your S-corp salary, your quarterly estimates, and the coordination between your business and personal returns.
Getting your S-corp salary right
What “reasonable compensation” actually means
If you’re operating as an S-corp, you’re required to pay yourself a “reasonable” W-2 salary before taking distributions. The IRS defines reasonable as what you’d pay someone else to do your job. That standard is intentionally vague — and that’s where planning lives.
Set your salary too low and you risk an IRS audit that reclassifies distributions as wages — triggering back payroll taxes, penalties, and interest. Set it too high and you’re over-paying FICA and self-employment tax unnecessarily.
FICA rate on W-2 wages
15.3%
Split between employer and employee — but as an S-corp owner, you pay both sides on your salary.
The right salary is defensible, documented, and calibrated to your role — not a round number someone picked years ago.
What sets your salary range
- BLS wage data for your role and industry — the IRS uses this as a benchmark
- Hours you work in the business and your specific duties
- Gross revenue of the business (higher revenue supports a higher salary)
- Whether you’re the sole owner-operator or one of several working owners
- Comparable salaries in your market for similar roles
Common mistake
Interactive Tool
S-Corp Salary Calculator
Estimate an IRS-defensible reasonable compensation range based on your role, industry, and business revenue. See your potential SE tax savings and audit risk.
Your details
Fill in your details and click Calculate to see your estimated reasonable compensation range.
Quarterly estimates that aren't guesses
Quarterly estimates are advance payments on the income tax you expect to owe. For S-corp owners, this means accounting for both your W-2 withholding and the pass-through income from the business.
Most owners underpay because they estimate from their bank balance instead of from actual profit. A well-run set of books makes the difference between a guess and a calculation.
The two safe-harbor methods
You can avoid underpayment penalties by paying either:
- 90% of current-year tax — requires an accurate estimate of this year’s income
- 100% of prior-year tax — straightforward if your income is similar to last year (110% if AGI exceeded $150k)
In practice, most business owners use the prior-year safe harbor for simplicity, then catch up with a large Q4 payment when they have a clearer picture of the year.
S-corp specific considerations
Your W-2 withholding from the S-corp salary counts toward your quarterly payment obligation. If your salary has meaningful withholding, you may owe less in estimated payments than you think. This is why salary and estimates need to be looked at together.
The goal is not to minimize your quarterly payments — it’s to never be surprised by what you owe.
Interactive Tool
Quarterly Estimate Planner
Enter your estimated business profit, entity type, and prior-year tax to calculate your 2026 quarterly payment amounts and due dates.
Tax Planning
Know when your quarterly estimates are due.
Quarterly estimates are due on specific dates — missing them triggers penalties. Enter your expected income and see all four due dates, amounts, and payment instructions at a glance.
Your numbers
Net self-employment income after business expenses
Annual Estimate
Estimated at 35% federal + SE tax + state
Total Annual Tax
$178,800
Per Quarter
$44,700
Per Month
$14,900
Quarterly Schedule
Q1 — Due January
Deadline: April 15
Payment
$44,700
Q2 — Due April
Deadline: June 15
Payment
$44,700
Q3 — Due July
Deadline: September 15
Payment
$44,700
Q4 — Due October
Deadline: January 15 (next year)
Payment
$44,700
Payment Instructions
Safe Harbor
Pay 100% of last year's tax (110% if AGI was over $150k) to avoid penalties. If this is your first year, estimate conservatively.
Using IRS Direct Pay (irs.gov)
Go to irs.gov/payments — no registration required. Instant confirmation.
Three things to do right now
- 01Put all four dates in your calendar. April 15, June 15, September 15, January 15. Set a reminder two weeks before each one. Missing a deadline because you forgot is the most avoidable mistake here.
- 02Open a dedicated tax savings account. Move 25–30% of every payment you receive into a savings account you don’t touch. Label it “taxes.” When payment day arrives, the money is already there.
- 03Make your next payment at IRS.gov/payments. IRS Direct Pay is free, takes about five minutes, and gives you an instant confirmation number. No account setup required. If you’re in California, also pay at ftb.ca.gov/pay.
Business and personal return coordination
Your S-corp return (Form 1120-S) and your personal return (Form 1040) are not independent. The profit from the S-corp flows to your K-1, which flows to your 1040. The salary you paid yourself shows up in both places.
When the business return and personal return are handled separately — different CPAs, or the same CPA but without a unified view — errors and missed opportunities compound. The person preparing your 1040 needs to know what’s on the business side.
What coordination looks like
- Your CPA reviews the business K-1 before it lands on your 1040
- Retirement contributions on the business side reduce pass-through income before it hits your personal return
- Any Section 179 or bonus depreciation decisions are made with the personal return in mind
- Estimated payment adjustments are coordinated between business and personal cash flow
If your CPA sends you one engagement letter for the business and a separate one for your personal return with separate fees and no obvious connection — ask who’s looking at both together.
The October CPA conversation
The most valuable conversation you can have with a CPA happens in October or November — when the year is close enough to estimate accurately, but early enough to act.
What should happen in that conversation:
- Review year-to-date profit and project the full-year number
- Check whether your W-2 salary and quarterly estimates are on track
- Identify any deductions you can still take before December 31
- Decide whether a retirement contribution makes sense this year
- Confirm your Q4 estimate is sized correctly to avoid a penalty
If your CPA only contacts you in January or February when they need your documents, that’s a signal. Reactive filing is not the same as proactive planning — and the difference shows up on your check to the IRS.
What to ask your CPA in October
Questions about this guide
Common questions
- The October planning sprint is 2 hours, once a year. Quarterly reviews are 15 minutes each — four of them, so 1 hour total. Call it 5 hours a year, spread across the calendar. That's the time investment for going from reactive filing to proactive planning.
- Both. Organizing your picture earlier creates decisions that save money — retirement contributions, income timing, deduction acceleration, QBI optimization. Owners in the $400–800k revenue range typically find $5–22k in first-year savings when they start planning in October instead of March.
- If your CPA contacts you in October to review your picture, you may not need to change much. But if your CPA only shows up at filing time, they're documenting what happened — not shaping what happens next. The decisions that save money all have year-end deadlines, and December 31 comes faster than it seems.
- Yes. These worksheets are designed to structure the conversation you'd have with any CPA. Bring the completed October Planning Worksheet to your CPA in October and ask them to walk through it with you. That single conversation often surfaces more savings than the whole prior year.
How much time does this actually take?
Will this actually lower my taxes, or just organize them better?
My CPA already handles everything. Do I still need this?
Can I use these worksheets with my existing CPA?
Keep going
This guide covers the concepts.
The tools help you run your own numbers.
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Educational content only. This guide is for informational purposes and does not constitute tax, legal, or investment advice. Every situation is different — consult a qualified CPA and financial advisor before acting.