FuckWhatDay

Now with exactly eight instructions

Know what day it is.
Eventually.

FuckWhatDay is the industry's first enterprise grade Gregorian weekday resolution platform written entirely in Brainfuck. You give it a date. It gives you the day. Between those two events it executes several hundred thousand instructions, none of which were strictly necessary.

No part of the calculation is delegated to a sensible programming language.

Try it in your browser Read the source, if you dare

FuckWhatDay exists because WhatDay already solved this problem sensibly.

A pink brain wearing sunglasses with question marks in the lenses, holding a calendar

Trusted by absolutely nobody, including:

  • The Department of Redundancy Department
  • Calendars Anonymous
  • The Year 1900 (not a leap year)
  • Big Tuesday
  • Your Wristwatch, reluctantly

Take the tour you did not ask for

Demo Run the real program in your browser Watch a few hundred thousand instructions conclude that it is Sunday. Features Eight instructions. No roadmap. Full Gregorian compliance, judgemental validation and a principled refusal to read your clock. Engineering Benchmarks against a calendar Plus how it actually works, for the auditors. Pricing Free. Also free. Or real. Plus testimonials from a Tuesday, a calendar and the year 1900. FAQ Frequently avoided questions Why? Mostly why.