During a live session on April 7, 2026, Collective’s Marissa Achanzar broke down the April 15 tax deadline for solopreneurs, why it actually covers three separate things, how a tax extension works for self-employed filers, and how extension payments differ from a quarterly estimated tax payment.
What’s Actually Due for the April 15 Tax Deadline
The April 15 tax deadline represents three separate items, and they cover two different tax years. That overlap is what makes the date confusing.
- Filing your 2025 individual tax return. Your personal federal income tax return (Form 1040) is due, covering all household income, your self-employment activity, a spouse’s W-2, rental income, and investment income. S Corp owners need their Schedule K-1 from the business return before filing this.
- Extending your 2025 individual tax return. If you need more time, filing Form 4868 gets you an automatic six-month extension to file. It does not extend the deadline to pay what you owe.
- Your 2026 Q1 estimated tax payment. This is a separate, forward-looking payment covering income earned January 1 through March 31, 2026, toward your current-year tax bill.
April 15 is the standard annual deadline; it shifts when it lands on a weekend or holiday. Even if you extend your return, both the extension payment and the Q1 estimated payment are still due on this date.
Filing a Tax Extension for Solopreneurs
A tax extension is a formal request to the IRS for more time to file, not more time to pay. Most states follow the same six-month window, though some require a separate state-level extension request.
| What gets extended | What does not get extended |
|---|---|
| Your filing deadline, six additional months | Your payment deadline, still due by the original date |
| More time to gather documents (K-1s, closing out books) | Estimated tax payments, no extension available for these |
| More time to complete a complex return | State filing, some states require a separate extension request |
| Protection from late-filing penalties | Penalties and interest on unpaid tax, these still start accruing April 15 |
There’s no reason required to file a tax extension, and it’s free at the federal level (outside of any extension payment you owe). A common pattern for solopreneurs: if you extend an S Corp or other pass-through business return, you’ll generally extend your personal return too, since your personal filing depends on the K-1 that comes out of the business return.
Business and personal returns follow a set order and a linked timeline:
| Date | What’s due |
|---|---|
| March 16 | S Corp business return due or extended |
| April 15 | Personal tax return due or extended |
| September 15 | Extended deadline for the business tax return |
| October 15 | Extended deadline for the personal tax return |
Extension Payments vs. Estimated Tax Payments
An extension payment and an estimated tax payment get confused constantly, mostly because they land on the same date once a year. They cover different tax years and work differently the rest of the time.
| Extension payment | Estimated tax payment | |
|---|---|---|
| Year it applies to | Prior year (paying your 2025 bill in 2026) | Current year (paying into your 2026 bill throughout 2026) |
| Frequency | One-time, due April 15 | Quarterly (April 15, June 15, September 15, January 15) |
| Purpose | Covers the estimated balance owed on your annual return | Covers income and self-employment tax as you earn it |
| Timing | Made when you file your extension request | Paid on a rolling schedule tied to when income is earned |
| If you get it wrong | Overpayment refunded at filing; underpayment may carry minor penalties and interest | Underpayment triggers a separate penalty |
| State implications | A separate state-level payment may be required | A separate state-level payment may be required |
April 15 is the only date where both payment types can be due at once: an extension payment for 2025 (if you’re extending and expect to owe) and your Q1 estimated tax payment for 2026. The other estimated tax deadlines (June 15, September 15, January 15) only involve the current-year payment.
To estimate either payment, the general approach is the same: total up your actual and estimated income for the relevant period (business profit, a spouse’s W-2, rental income), apply a rough tax rate, then subtract anything you’ve already paid in through withholding or prior estimated payments. The remainder is what’s due.
“I have not done my taxes yet either. It’s a very human thing to procrastinate on things that are confusing or overwhelming.”
Avoiding Underpayment Penalties: Safe Harbor Rules
An estimated tax payment is a good-faith estimate, not a final number, so the IRS gives you a way to avoid an underpayment penalty even if your guess turns out low. This is called safe harbor, and under current law it works two ways, you only need to meet one:
- Pay at least 90% of your current year’s total tax, or
- Pay at least 100% of last year’s total tax (110% if your prior-year adjusted gross income was over $150,000, or $75,000 if married filing separately)
Meeting either threshold stops the underpayment penalty from accruing, even if you still owe a balance when you file. The first quarter’s estimate doesn’t need to be exact. Any payment toward your April 15 tax deadline obligations is generally better than none, and subsequent quarters give you room to true up as the year plays out.
If you end up owing more than you can pay in full, the IRS offers installment agreements. Balances of $10,000 or less generally qualify for a guaranteed agreement with minimal requirements; balances up to $50,000 generally qualify for a streamlined agreement without full financial disclosure. Either way, it has to be requested proactively, similar to a filing extension, and interest continues to accrue even while penalties are paused.
How Collective Supports Solopreneurs Year-Round
Collective supports solopreneurs at either stage of their tax status. For Members on the simpler single-member LLC profile, that includes LLC formation, monthly bookkeeping, invoicing, and annual individual tax filing. For S Corp Members, Collective also handles the payroll setup an S Corp election requires (since that reasonable salary is the mechanism for the self-employment tax savings), plus preparing and filing the separate business tax return. Either way, Members get a dashboard with built-in deadline reminders for the April 15 tax deadline and every estimated tax payment after it, access to an in-house team across formation, bookkeeping, tax, and payroll, and Collective Community, a network for connecting with other solopreneurs.
FAQ: April 15 Tax Deadline Questions for Solopreneurs
Live Q&A, questions consolidated by theme.
I owe tax but never made an estimated tax payment during the year. How do I actually pay what I owe?
Once your return is filed and shows a balance due, you can pay directly through the IRS’s official payment site (the .gov version), where you’ll enter your Social Security number, select the tax year the payment applies to (2025, for a balance from last year’s return), and pay the amount shown as owed. You’d repeat a similar process at the state level if your state has income tax.
I just formed my LLC this year. When do I start making estimated tax payments, and how do I calculate the first one?
You start with the estimated tax deadline that follows your first profitable activity. For an LLC formed in February, for example, your first quarter of activity is covered by the April 15 tax deadline. To estimate the payment, total your income for that quarter, apply a rough combined rate (a common shorthand is your income tax bracket plus the 15.3% self-employment tax rate), and pay in what you can. Any payment is better than none, and you can true up the estimate at the next quarterly deadline once you have more real data.
I have a W-2 job and a side business. Do I still need to make estimated tax payments?
Generally yes, though your W-2 withholding gives you some cushion since you’re already paying into your tax bill through that job. The issue is that withholding is calculated based on your W-2 wages alone, so it typically doesn’t account for the additional income from your side business. If that side income is relatively small compared to your W-2 income, the gap may be minor; as it grows, estimated tax payments (or increased W-2 withholding, see below) become more necessary to avoid an underpayment penalty.
Can I increase my W-2 withholding instead of making separate estimated tax payments for my side business?
In some cases, yes. If your side business income is relatively low relative to your W-2 income, bumping up withholding at your corporate job can cover the additional tax owed, which simplifies things since you’re not tracking a separate payment schedule. This depends heavily on your full tax picture (a spouse’s income, if filing jointly, and how much the side business actually earns), and it stops being a reliable solution once the side business grows enough that withholding alone can’t keep pace.
Am I expected to pay my whole tax bill at once if I owe? Are payment plans available?
The IRS generally expects full payment, but installment agreements are available if you can’t pay in full. Balances of $10,000 or less typically qualify for a guaranteed agreement; balances up to $50,000 typically qualify for a streamlined agreement without extensive financial disclosure. You have to request one proactively, and interest continues to accrue during the agreement even though late-payment penalties are paused.
Does Collective help with back taxes or negotiating with the IRS?
No, Collective doesn’t offer standalone tax resolution services for prior-year issues. The focus is on getting the current tax year handled correctly going forward.
Does California’s $800 annual fee apply to S Corps as well as LLCs?
Yes, but the mechanics shift once you elect S Corp status. As an LLC, the $800 is a flat annual minimum fee, that increases based on your gross receipts. Once you add an S Corp election, that $800 becomes a minimum tax rather than a flat fee, specifically the greater of $800 or 1.5% of your California business profit. Either way, expect at least $800 annually if you have a business entity in California. Other state fees and taxes vary.
Additional Resources
A few attendees asked about comparing S Corp status to staying a sole proprietor or SMLLC, and what profit or business markers signal it’s time to consider switching. That’s a deeper topic than this session covered – click here to read a recap of our session LLC v. S Corp: Which is Right for Your Business?
This content is for educational purposes only and does not constitute legal, financial, or tax advice. It reflects information shared during the April 7, 2026 session and general guidance current as of that date; tax rules and thresholds referenced may have changed since. Rules vary by state and individual circumstances, so consult a traditional accounting firm or tax professional about your specific situation.
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With over eight years in public accounting, Marissa has worked closely with small business owners to navigate tax strategy and compliance. At Collective, she translates complex tax concepts for self-employed individuals into clear, practical content—supporting them on their tax journey so they feel informed, confident, and empowered to make decisions for their business.