Tax Planning
2026 Small Business Tax Deadlines You Can't Miss
Why these dates matter more than you think
Missing a deadline doesn't just mean a late return, it usually means a penalty, and penalties compound. Here's the calendar we keep our own clients on, in plain language.
The key dates
January 15: Q4 estimated tax payments due. January 31: W-2s and 1099s due to recipients. March 15: S-corp and partnership returns due (or extension deadline). April 15: Individual and C-corp returns due, and Q1 estimated payments. June 15: Q2 estimated payments due. September 15: Q3 estimated payments due, and extended S-corp/partnership returns due. October 15: Extended individual returns due.
The real fix: don't rely on remembering this list
The businesses that never miss a deadline aren't the ones with the best memory, they're the ones with a bookkeeper or tax planner already tracking it for them. That's the whole point of year-round support instead of a once-a-year phone call.