DEADLINES · REMINDERS
Tax Calendar & Reminders
One calendar for every deadline that applies to you: US quarterly estimated tax and Form 1040, Form 5472 and Form 7004 for a foreign-owned LLC, Wyoming or Delaware annual filings, and UK Self Assessment and Making Tax Digital. Download it once and your phone reminds you two weeks before each date.
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Federal US dates are adjusted for weekends and legal holidays; UK and state dates are shown as published. Reminders only, not tax advice. See our full disclaimer.
Primary sources
Links checked Sep 24, 2026
- IRSPublication 505 — Tax withholding and estimated taxQuarterly due dates; 90% / 100% / 110% safe harbor
- IRSPublication 509 — Tax calendars (legal holidays)Due dates on weekends and legal holidays, including DC Emancipation Day
- IRSInstructions for Form 5472Foreign-owned US DE filing, reportable transactions, $25,000 penalty
- IRSAbout Form 7004 (automatic extension)Six-month extension to October 15
- Delaware Division of CorporationsLLC/LP/GP annual tax instructions$400 annual LLC tax due June 1; $200 penalty plus 1.5% monthly interest
- Wyoming Legislature, W.S. 17-29-209 (archived copy)Annual report for secretary of state (LLCs)Due the first day of the month of organization; license fee $60 or $0.0002 of Wyoming assets, whichever is greater
- GOV.UKSelf Assessment tax returns: deadlines5 October registration, 31 October paper, 31 January online return and payment
- GOV.UKUnderstand your Self Assessment bill: payments on account31 January and 31 July; not due under £1,000 or if over 80% collected at source
- HMRCCheck if you're eligible for Making Tax Digital for Income Tax£50,000 from April 2026, £30,000 from 2027, £20,000 from 2028
- HMRCSend quarterly updates (Making Tax Digital for Income Tax)Update deadlines 7 August, 7 November, 7 February, 7 May
Rules change. Where our summary and the authority differ, the authority wins. See how every figure is sourced on the sources & methodology page.