Five 21-day plans · for after dark, mostly
Your phone has slept with you long enough.
Example: day 8 of 21
Pick one plan. Up to three habits a day for 21 days. On day 21, a chart that compares you with one person: you, three weeks ago.
Free during the beta. No card, so nothing to forget to cancel. How lifetime places work
Five plans. Pick your problem.
Each one runs 21 days. Switch whenever.
Three habits a day. Small enough to do half asleep.
Most take a few minutes. The walking plan wants an actual walk.
Up at your wake-up timeSame time every day done
Caffeine cutoff8 hours before bed not done yet
Bed is for sleepAwake in bed? Get up not done yet
Evening wind-downOptional · 10 min optional
Magnesium add-onOptional · starts today optional
MoodCalm done
A sample day for a made-up person called Maya.
- Up to three required habits a day.
- Optional extras you can skip.
- Supplements are never required.
- Missed Thursday? It stays on the chart. No streak to cry over.
How was it for you?
Seven moods, one tap. It’s half of what your recap runs on.
- optimistic Friendly
- angry Passionate
- happy Loving
- enthusiastic Energetic
- balanced Renewed
- focused Creative
- peaceful Calm
Choose your wake-up timeset-up set-up, day 1
Choose your caffeine cutoffset-up set-up, day 1- Up at your wake-up time required, days 2 to 21
- Caffeine cutoff required, days 2 to 21
- Bed is for sleep required, days 3 to 21
- Evening wind-downoptional optional, days 5 to 21
- Magnesium add-onoptional · never required optional, days 8 to 21
Why these habits
- Up at your wake-up time A fixed wake-up time is part of CBT-I, the first treatment recommended for long-term insomnia. Clinical guideline · AASM guideline, 2021
- Caffeine cutoff Caffeine six hours before bed still disrupted sleep in a lab study. A review suggests about 8.8 hours. Small trial; meta-analysis · Drake et al., 2013; Gardiner et al., 2023
- Bed is for sleep Leaving bed when you can’t sleep is a recommended part of CBT-I. Clinical guideline · AASM, 2021; Furukawa et al., 2024
The only one you’re compared with is you.
Your own first days, not a stranger’s average. Results say still forming until day 14, because two good nights prove nothing.
Still forming until day 14
Example data for a made-up person: sample data, not a result anyone got. A trend in one person’s own data, not a diagnosis. Early results say still forming until day 14 (our rule, not a study).
Health connections are optional: Apple Health on iPhone, Health Connect on Android, and Oura in the app on either phone.
- Apple Health
- Health Connect
- Oura
Day 8: a quick check-in. No pressure.
A short look back at week one, then you decide whether to keep going. Stopping never counts against you.
Write a plan for your clients.
Build a 21-day plan in Creator Studio on the web, and your clients follow it in the app for free. Paid selling isn’t live yet. When it is, coaches keep 80% after processing fees.
For coaches200 lifetime places
Free while the beta lasts.
- Now
- Every feature is free during the open beta. No card. We haven’t set an end date.
- A lifetime place
- Finish your first full 21-day plan during the beta with at least 80% of its required habits done and, if fewer than 200 people have qualified before you, Explorer is yours for life straight away.
- Stopped early?
- It doesn’t count against you. The first plan you run to its end is the one that counts.
- Places claimed
- 1 of 200 · read live from our server
- After the beta
- One active plan, daily habits, mood, recaps and your history stay free. Explorer, the paid tier, adds every plan and connected health readings.
- Medical
- By Day is a wellness app, and it doesn’t diagnose or treat any condition. If something’s worrying you, talk to a clinician.
Questions people ask
More answers in SupportWhy not just use my notes app?
You can. Pick one habit, tick it off for 21 days, and compare the first week with the last. If you'd stick with it, that works fine. What By Day adds is the plan itself: which habits, in what order, and the evidence for each one. It also adds a check-in on day 8 and does the comparison for you, including sleep or steps if you connect them. If a notebook is already working, keep the notebook.
Why 21 days?
It gives you a few first days to compare against and two more weeks to see whether anything moved. There's nothing magic about the number.
What is included during the beta?
The open beta is running and has no end date yet. Every feature is free: every plan, connected health readings, home screen widgets, offline habit logging, recaps and your full history. No card is needed.
What happens after the beta ends?
Your account and history stay. The free tier lets you run one active plan at a time. Explorer, the paid tier, adds every plan and connected health readings. Finish your first full 21-day plan during the beta with at least 80% of its required habits done and, if fewer than 200 people have qualified before you, Explorer is yours for life straight away. A plan you stop early doesn't count against you; the first one you run to its end does.
Do I need a wearable?
No. Every plan works with the habits and your own ratings. Connecting Apple Health, Health Connect or Oura adds readings to compare.
How long does it take each day?
Every plan shows its daily time before you start. Many habits take a few minutes, and the walking plan takes longer. Habits aren't locked to a time of day.
What if I miss a day?
The plan carries on. The missed habit stays visible, and the recap shows it.
Can I change plans partway through?
Yes. Starting a new plan ends the current one, and the app asks you to confirm first. The days you've done stay in your history with a recap.
Is my health data private?
Your account starts private. You choose which health categories By Day can read, and you can change that on your phone. We don't sell health data or use it for advertising. You can delete your account and its data from Settings.
Where can I use it?
On iPhone through the App Store and on Android through Google Play. Coaches and creators write plans in Creator Studio on the web.
Start a 21-day plan.
Pick one tonight. Day 1 is mostly set-up. Easy first date.
Occasional updates
Hear when a new plan ships.
A short note when a new plan or a meaningful change is ready. One confirmation email first, and no spam.