Pick a challenge.
Check off the days.
Keep the streak alive.
Free calendar trackers for any challenge - 75 Hard, 30 days without sugar, 100 days of code, or anything you invent. Streaks, badges, day notes, shareable progress and printable calendars.
No app to install · works on your phone · free forever
How it works
Create your calendar
Pick one of our ready-made challenges or invent your own - any title, any length from 7 to 730 days, starting whenever you like.
Check off each day
One tap marks the day done. Honest about a bad day? Mark a miss - the calendar tells the true story, and comebacks earn badges too.
Watch the streak grow
Current streak, best streak, completion percentage, achievement badges, and a share link that lets friends follow along live.
Popular challenges to start today
75 Hard
The famous 75-day mental-toughness program: no substitutions, no rest days, no excuses.
75 days 💪30-Day Fitness Challenge
Thirty days of daily movement - you pick the workout, the calendar keeps you honest.
30 days 🍬30 Days No Sugar
Cut added sugar for 30 days and reset your taste buds.
30 days 💻#100DaysOfCode
Code for at least an hour every day for 100 days.
100 days 🧘30 Days of Meditation
Ten minutes of meditation every day for a month.
30 days 💰No-Spend Month
30 days of zero non-essential spending.
30 daysEverything a challenge needs
Streaks & stats
Current streak, best streak, days left and completion % - computed live, screenshot-worthy.
Achievement badges
From First Step to the 365 Club - twelve badges earned automatically as your calendars fill up.
Do it together
Send one invite link and friends join with their own calendars. A shared leaderboard keeps the whole group honest.
Day notes
Attach a note to any day - what you did, how it felt, the number that mattered.
Printable calendars
Every challenge exports to a beautiful printable calendar for the fridge - also available without an account.
Calendar app export
Download any challenge as an .ics file and see “Day 12 of 30” inside Google or Apple Calendar.
From the guides
How Long Does It Really Take to Build a Habit?
The truth behind the 21-day myth, what the 66-day research actually found, and how to pick the right challenge length.
6 min readThe 75 Hard Rules, Explained Properly
All five daily tasks of 75 Hard, the restart rule, common mistakes, and whether you should attempt it at all.
7 min readNever Miss Twice: How to Survive Breaking Your Streak
Missing one day of a challenge costs almost nothing - unless it becomes two. The psychology of the comeback, and rules for it.
5 min readDay one is a checkbox away.
Free account, no app, thirty seconds to your first calendar.
Create your challenge calendar