April 15 - Social Security, Medicare and Withheld Income Tax
If the monthly deposit rule applies, deposit the tax for payments in March.
April 15 - Corporations
The first installment of 2015 estimated tax of a calendar year corporation is due.
April 15 - Partnerships
File a 2014-calendar year return (Form 1065). Provide each partner with a copy of Schedule K-1 (Form 1065), Partner’s Share of Income, Deductions, Credits, etc., or a substitute Schedule K-1. If you want an automatic 5-month extension of time to file the return and provide Schedules K-1 or substitute Schedules K-1 to the partners, file Form 7004. Then, file Form 1065 and provide the K-1s to the partners by September 15.
April 30 - Social Security, Medicare and Withheld Income Tax
File Form 941 for the first quarter of 2015. Deposit or pay any undeposited tax under the accuracy of deposit rules. If your tax liability is less than $2,500, you can pay it in full with a timely filed return. If you deposited the tax for the quarter in full and on time, you have until May 11 to file the return.
April 30 - Federal Unemployment Tax
Deposit the tax owed through March if it is more than $500.