April 17, 2018 @ 12:00 am - April 18, 2018 @ 12:00 am Household Employers: File Sch. H with Form 1040 if you paid $2,000 or more to a household employee.
April 17, 2018 @ 12:00 am - April 18, 2018 @ 12:00 am Corporations: Deposit the first installment of your 2018 estimated tax.
April 17, 2018 @ 12:00 am - April 18, 2018 @ 12:00 am Corporations: File Form 1120 for calendar year and pay any tax due. For automatic 6-month extension, file Form 7004 and deposit estimated tax.