Ebb
See the caffeine in you, and when it lets you sleep
That 4 pm latte is still with you at midnight. Ebb shows how much caffeine is in you right now, when it falls under your sleep line, and the last time today one more cup still lets you sleep.
App Store link coming soon
How it works
Log a drink with one tap. Ebb adds up every coffee, tea, energy drink and cola into one number, and tells you what it means for tonight.
The curve
Caffeine rises over the first hour after a drink, peaks about 45 minutes in, then slowly ebbs away. Ebb draws that curve for the whole day.
Your sleep line
Pick your bedtime and how much caffeine you are fine with at night, 50 mg to start. Ebb tells you when you will be under it: "Under your sleep line at 21:40".
Last call
The latest time today your usual drink still clears by bedtime. Ebb can remind you 20 minutes before.
What if
Pick a drink and see what it would do before you log it: "Moves your sleep-ready time 1 h 10 min later, to 23:50".
Caffeine in you now
98mg
- Under your sleep line at 14:54
- One more Latte or cappuccino before 13:17 still clears by bedtime
- Espresso now?Moves your sleep-ready time 3 h 39 min later, to 18:33
Example: a latte at 08:00, seen at 10:00, with a 23:00 bedtime and a 5-hour half-life.
Your nightsEbb Plus
Does a late coffee change how you sleep? Ebb compares your own nights and tells you only what the numbers support.
Your sleep pattern
Answer "How did you sleep?" in the morning with Good, Okay or Poor, right from the notification. Or turn on Apple Health, and Ebb reads how long you slept from your watch or sleep app.
After 14 nights, Ebb Plus compares the nights you went to bed over your sleep line with the rest. It needs at least five of each, and it names a difference only when a statistical test says chance explains it poorly. Often the answer is "No clear difference yet", and that is worth knowing too.
On nights with 50 mg or more at bedtime, you slept 34 min less on average (21 nights).
Everywhere you drink coffee
Log from wherever is closest. Everything stays in step between your iPhone and your watch.
Apple Watch
See the caffeine in you and your sleep line, and log a favorite in one tap; turn the crown to change the amount. Complications for your watch face are free.
Widgets
Caffeine now on the Home Screen and the Lock Screen, and the whole day's curve with your last call. With Plus, a widget that logs your favorites in one tap.
Control Center
A control that shows your caffeine and opens Ebb. With Plus, one that logs your chosen drink from Control Center, the Lock Screen or the Action button.
Siri and Shortcuts
"Log espresso in Ebb". "How much caffeine is in me in Ebb". "When can I sleep in Ebb".
Private by design
- No account, no ads, no analytics. Ebb has no server and makes no network requests of its own.
- Your drinks, morning answers and settings stay on your iPhone and Apple Watch. We never receive them.
- Apple Health is optional. If you turn it on, Ebb saves the caffeine you log there and reads your sleep, and uses that for nothing else.
Read the privacy policy.
Free, with Ebb Plus when you want more
Everything you need to see your caffeine and your sleep line is free.
Ebb
Free
- Over 20 drinks built in, from espresso to matcha
- The curve, your sleep line and your last call
- What a drink would do before you log it
- Last-call reminder
- Morning sleep check-in
- 7 days of history
- Apple Watch app and complications
- Caffeine now and curve widgets, Lock Screen widgets, the Control Center control and Siri
Ebb Plus
14.99 USD a yearwith a one-week free trial, or 2.99 USD a month
- Your sleep pattern: caffeine at bedtime against how you slept
- Your own half-life, from 2 to 10 hours
- Your own drinks, with their real caffeine
- Full history with 30- and 90-day charts
- Export your log as CSV
- One-tap logging from a widget and from Control Center
Prices are in US dollars. The App Store shows the price for your country, which may differ. Payment is charged to your Apple ID. Subscriptions renew automatically unless cancelled at least 24 hours before the end of the trial or the current period. Manage or cancel them in your App Store account settings.
Questions
How accurate is it?
Ebb's numbers are estimates. Each drink starts from a typical amount from food tables, and real cups vary: one café's espresso can hold a lot more than another's. You can change the amount every time you log. How fast caffeine leaves you varies a lot from person to person, so Ebb lets you pick fast, typical or slow, or with Plus your own half-life. Use the times as a guide for your evening, not as a measurement.
What is a half-life?
The time your body takes to clear half of the caffeine in it. Most adults take three to seven hours. With a five-hour half-life, a 100 mg coffee at 14:00 still leaves about 50 mg at 19:00 and about 25 mg at midnight. That long tail is why an afternoon cup can still be with you at bedtime.
Why is my number not going up right after I log a drink?
Caffeine is absorbed over the first hour, so the number starts low and climbs, peaking about 45 minutes after you drink. If you log a drink you had a while ago, pick "15 min ago", "30 min ago", "1 h ago" or an earlier time, and Ebb places it on the curve where it belongs.
What is the sleep line?
How much caffeine you are fine with still having in you at bedtime: 25, 50, 75 or 100 mg. It starts at 50 mg, about half a cup of filter coffee. Ebb uses it for your sleep-ready time, your last call and your sleep pattern.
Does it work without Apple Health?
Yes. Apple Health is optional. Without it, your log stays in Ebb and your sleep pattern uses your morning answers. With it, Ebb also saves your caffeine to Health and compares how long you slept.
What about pregnancy and medicines?
Ebb uses the same standard model for everyone. Pregnancy and some medicines can change how fast caffeine leaves your body, sometimes by a lot. Ask your doctor or midwife how much caffeine is right for you.