If  the deadline falls on a weekend or holiday, the next business day is the deadline:

January 15:
– 4th Qtr estimated payment due
– 4th Qtr payroll filings due

January 31:
– W2s, 1099s must be sent to payee and filed with IRS

March 15:
– Partnership (1065) and S Corp (1120S) must be filed or extension filed with IRS and state tax agencies.

April 15:
– Personal tax returns and corporate tax returns (1120) must be filed or extension filed
– 1st qtr estimated payments due
– 1st Qtr Payroll filings due

May 15:
– Non-profit tax returns (990) must be filed or extension filed

June 15:
– Personal tax returns for persons outside the USA on April 15 due
– 2nd Qtr estimated payment due
– 2nd Qtr payroll filings due

September 15:
– Deadline for filing Partnership (1065) and S Corp (1120S) on extension
– 3rd Qtr estimated payment due
– 3rd Qtr payroll filings due

October 15:
– Deadline for filing personal and corporate (1120) tax returns on extension)