Small business tax deadlines you can't afford to miss in 2026

Quarterly estimates, payroll filings, and annual returns all land on different clocks, and missing any one of them means penalties that are entirely avoidable with a bit of planning.

For most small businesses, quarterly estimated tax payments are due in mid-April, June, September, and January. Payroll tax deposits and filings run on their own separate federal and state schedules, often monthly or quarterly depending on your deposit frequency. Sales tax filing deadlines vary by state and by how frequently you collect.

The simplest solution is a single shared calendar that consolidates every deadline in one place, with reminders set two weeks ahead so there's time to gather documents and review numbers before anything is due. We build this calendar for every client we work with, so nothing ever depends on memory.