If you’re building a startup, taxes probably sit somewhere between “I’ll deal with it later” and “Oh no, the deadline is tomorrow.” We get it, you didn’t start a company to file Form 1120 or chase W-9s from contractors.
But here’s the thing: ignoring taxes costs real money. Penalties, interest, lost deductions — they all eat into your runway. And the worst part? Most of it is 100% avoidable.
This guide is for founders who want to focus on building, not bookkeeping, but still keep the IRS happy.
If you run a U.S. startup (especially a Delaware C-Corp), these are the big ones:
| Date | Form | Why It Matters |
|---|---|---|
| Jan 31 | W-2 / 1099-NEC | Give these to employees & contractors |
| Mar 1 | Delaware Franchise Tax | $200 late fee if missed |
| Apr 15 | Form 1120 + Q1 Estimated Tax | Corporate tax return & first payment |
| Jun 15, Sept 15, Jan 15 | Estimated Tax Payments | Avoid underpayment penalties |
💡 Pro tip: Use TaxHero AI’s Startup Tax Calendar to get all these dates auto-loaded and get reminders before they sneak up on you.
Simply answer a few questions and get the calendar in seconds, plus automated reminders to your email.
Click here - Tax Calendar
Yes, even that $12 Figma subscription and the $6 coffee you bought before your investor meeting.
Why? Because deductions add up, and the IRS is picky about documentation.
Categories to watch:
Software & tools
Marketing spend
Travel & lodging (yes, that founder retreat counts)
Contractor payments
Office expenses
👉 See our guide: 7 Tax Deductions You Shouldn’t Miss in 2025
If you paid a freelancer or contractor $600+ this year, you owe them a 1099-NEC.
Mess this up and you risk:
IRS penalties
Disgruntled contractors
A mess during due diligence if you raise funding
Full walkthrough here: 1099s for Startups: The Complete Guide for Founders
Even if you’re pre-revenue, you might qualify for thousands back via the R&D Tax Credit.
If you’re building something new — code, prototypes, designs — you could reduce your payroll taxes by up to $250K over five years.
See: R&D Tax Credit for Startups: How to Save Big Before You Even Launch
Stop juggling spreadsheets and sticky notes.
Tools like TaxHero AI:
Generate your personalized tax calendar
Send deadline reminders
Help you file on time
Flag missing forms before it’s too late
Because you don’t need to be a tax expert, you just need to avoid expensive mistakes.
Taxes don’t have to be chaos. A little structure + the right tools = more money in your pocket and less stress in your head.
Bookmark this guide, send it to your co-founder, and if you’re ready to take the mental load off, get your TaxHero AI.
With AI-powered bookkeeping and tax filing, you stay focused on what matters: building your startup.
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