Here’s what you need to know filing business taxes for 2024.
A small business tax compliance checklist starts with your entity type, which decides the federal income tax return you file. From there it runs through estimated payments, payroll and information returns, state and franchise tax, and sales tax in every state where you have nexus. Here’s each piece, with the current filing season’s dates as the example.
Match your entity type to the right federal return
The IRS recognizes five business structures: sole proprietorship, partnership, corporation, S corporation, and LLC. Each maps to a specific federal return. Sole props and single-member LLCs report on Schedule C with Form 1040. Partnerships and multi-member LLCs file Form 1065. S corporations file Form 1120-S, and C corporations file Form 1120. Pass-through entities file first, so owners receive their Schedule K-1s in time to finish their personal returns. If you’re still choosing a structure, our guide to selecting a small business entity walks through the trade-offs. The table below lists the calendar-year deadlines, using this season’s 2026 dates as the example.
| Entity | Form | Original due date | Extended date |
|---|---|---|---|
| Partnership / multi-member LLC | Form 1065 | March 16, 2026 | September 15, 2026 |
| S corporation | Form 1120-S | March 16, 2026 | September 15, 2026 |
| C corporation | Form 1120 | April 15, 2026 | October 15, 2026 |
| Sole prop / single-member LLC | Schedule C with Form 1040 | April 15, 2026 | October 15, 2026 |
Partnership and S corporation returns are due the 15th day of the 3rd month after year-end. When the 15th lands on a weekend, the deadline shifts to the next business day, which is how March 15 becomes Monday, March 16 in 2026. C corporation and Schedule C returns are due the 15th day of the 4th month, generally April 15.
Estimated taxes and extensions
Income tax isn’t only due once a year. Owners of pass-through entities pay quarterly estimated tax with Form 1040-ES. Per the IRS Form 1040-ES instructions, the four installments for a calendar year fall in April, June, and September, then the following January. C corporations owe estimated tax in four installments due the 15th day of the 4th, 6th, 9th, and 12th months, figured on Form 1120-W and deposited through the Electronic Federal Tax Payment System (EFTPS). For the current season, the individual dates are April 15, June 15, and September 15, 2026, then January 15, 2027. Our breakdown of estimated tax timing covers the safe-harbor math.
Need more time to file? Entities file Form 7004 for an automatic six-month extension, and individuals file Form 4868. An extension moves the filing date, not the payment date. Any tax owed is still due at the original deadline, and interest plus the failure-to-pay penalty accrue on the unpaid balance from that date. Our guide to business tax extensions explains when an extension helps and when it just delays the pain.
Payroll and information returns
If you have employees or pay contractors, a second calendar runs alongside your income tax return. According to the IRS employment tax due dates, Form 941 reports payroll tax each quarter and is due the last day of the month after the quarter ends. Form 940 reports annual FUTA and is due January 31. Forms W-2 and W-3 go to employees and the Social Security Administration by January 31, and Form 1099-NEC goes to contractors and the IRS by the same date. When January 31 falls on a weekend, these shift to the next business day.
One threshold is changing. For tax year 2025 returns filed in early 2026, the old $600 Form 1099-NEC reporting threshold still applies. The IRS instructions for Forms 1099-MISC and 1099-NEC confirm the One Big Beautiful Bill Act raised that threshold to $2,000 for payments made on or after January 1, 2026, with the first filings under the new rule due in January 2027. Track contractor payments against the threshold that applies to the year you’re filing, not the year you’re paying.
State income and franchise tax
State obligations sit on top of federal, and they don’t always track your income. Delaware corporations owe an annual franchise tax and must file the franchise tax report by March 1 each year. According to Wolters Kluwer, missing that date triggers a $200 penalty plus 1.5% monthly interest on the unpaid balance, and the report is filed through the Delaware Division of Corporations. This catches many owners who formed in Delaware but operate somewhere else.
California charges an $800 minimum franchise tax on every LLC, corporation, and limited partnership registered in the state, owed regardless of income or activity, and generally due the 15th day of the 4th month. Nonpayment can lead to penalties, interest, and suspension of the entity’s rights. The takeaway is simple. Your state of formation, your state of operation, and every state where you have employees or property can each impose its own tax with its own form and its own date.
Sales tax and economic nexus after Wayfair
Sales tax is where a growing business quietly accumulates risk in states it has never set foot in. In South Dakota v. Wayfair, decided June 21, 2018, the Supreme Court let states require out-of-state sellers to collect sales tax based on economic activity alone. That is economic nexus. Per the Sales Tax Institute, South Dakota’s threshold is $100,000 in sales or 200 separate transactions into the state. Most states copied that model, but the outliers matter. California and Texas use $500,000 in sales with no transaction count, and New York requires $500,000 and more than 100 transactions, both together. All 45 states with a statewide sales tax, plus the District of Columbia, now have economic nexus rules.
The trend is toward the dollar threshold alone. As of early 2026, 16 states have dropped the 200-transaction trigger, with Illinois removing it on January 1, 2026, and Kentucky on August 1, 2026. Physical nexus still counts on its own, so employees, an office, or inventory in a warehouse each create a collection duty. Marketplace facilitator laws make Amazon, eBay, and similar platforms collect on their own sales, but your website and trade-show sales stay your responsibility.
The workflow is the same in every state. Determine where you have nexus, register for a sales tax permit, confirm which products are taxable, collect the correct combined state and local rate, then file and remit on the frequency the state assigns you. An annual sales tax check-up is the cleanest way to catch a new nexus line before it becomes a back-tax bill.
That wasn’t so bad, was it?
None of this is hard on its own. It gets hard at the seams. Bookkeeping that doesn’t match the return. A Delaware franchise notice nobody was watching. A sales tax registration that lapsed while revenue crossed a nexus line in three new states. A small business tax compliance checklist only works when one team owns every line of it, on a calendar, all year.
That’s the case for keeping the whole checklist under one roof. Indinero bundles bookkeeping, accounting, and business tax into one monthly engagement, so the team that keeps your books is the team that files your return. The tax position always matches the financials it came from. Nothing gets handed across a gap.
The other piece is breadth. Indinero serves the full range of entity types on this checklist, from sole proprietor and single-member LLC to multi-member LLC, S corporation, C corporation, and multi-entity structures. A business that starts as an LLC, elects S corp status, then converts to a C corp for a raise never has to switch providers or re-explain its history. The same engagement tracks federal deadlines, state and franchise tax, payroll filings, and multi-state sales tax nexus as you grow into new states.
That continuity isn’t a given. With continuous operations since 2009, the same team stays on your books year after year, so your prior filings don’t disappear when a vendor changes hands.
If you’d rather not run this alone, that’s what our business tax services and online bookkeeping teams are built for. Compliance shouldn’t feel like something you manage. It should feel like something that runs quietly in the background while you build the business.
Frequently asked questions
These are the questions small business owners ask most about staying tax-compliant.
What should be on a small business tax compliance checklist?
A small business tax compliance checklist has two halves, income tax and sales tax. Income tax means filing the right federal return for your entity type, making estimated payments, and completing payroll and information returns on time. Sales tax means registering and collecting wherever you have economic nexus. Indinero keeps both halves on one calendar, so nothing slips between the bookkeeping and the return.
Which federal tax return does my business entity file?
Your business entity type decides which federal return you file, from Schedule C for sole props to Form 1120 for C corporations. Partnerships file Form 1065, S corporations file Form 1120-S, and pass-through entities file first so owners receive their Schedule K-1s in time for personal returns. Indinero serves the full range of entity types, so a business that elects S corp status or converts to a C corp never has to switch providers.
Does filing a tax extension give me more time to pay?
No, a tax extension gives you more time to file, not more time to pay. Entities file Form 7004 and individuals file Form 4868 for an automatic six-month extension, but any tax owed is still due at the original deadline. Interest and the failure-to-pay penalty accrue on the unpaid balance from that date. Pairing bookkeeping and tax under one indinero engagement means your numbers are ready well before the payment is due.
What is economic nexus and when do I have to collect sales tax?
Economic nexus means a state can require you to collect sales tax based on your sales volume alone, even with no physical presence there. After South Dakota v. Wayfair in 2018, most states set a threshold near $100,000 in sales or 200 transactions, though California and Texas use $500,000. Indinero tracks multi-state nexus as you grow, so a new threshold gets caught before it becomes a back-tax bill.
When are quarterly estimated taxes due for a small business?
Quarterly estimated taxes for pass-through owners are generally due in April, June, and September, then the following January. Owners use Form 1040-ES, while C corporations figure estimates on Form 1120-W and deposit them through EFTPS on the 15th day of the 4th, 6th, 9th, and 12th months. Missing an installment triggers underpayment penalties, so indinero maps these dates onto the same calendar that tracks your annual return.
What changed with the 1099-NEC reporting threshold?
The 1099-NEC reporting threshold rose from $600 to $2,000 for payments made on or after January 1, 2026. For tax year 2025 returns filed in early 2026, the old $600 threshold still applies under prior rules. The first $2,000 filings are due in January 2027. Because indinero keeps your books and your filings on one team, contractor totals are tracked against the correct year automatically.
