First ThingSmart alarms explained: sleep-cycle alarms vs alarms that plan your morning
The short answer
"Smart alarm" means two different things. A sleep-cycle alarm picks a moment inside a window you set, when it thinks you're sleeping lightly. A planning alarm works out what time you need to be up in the first place, from your schedule. One chooses the minute; the other chooses the time.
Two kinds of smart
| Sleep-cycle alarm | Planning alarm | |
|---|---|---|
| The question it answers | When in the next 30 minutes is a good moment to wake? | What time do I need to be up tomorrow? |
| What it uses | Movement or sound from your phone, or a watch | Your usual week, your calendar, travel and getting-ready time |
| You still have to | Set the alarm and the window yourself | Check it, and correct it if it's wrong |
| Examples | Sleep as Android, Sleep Cycle | First Thing |
Do sleep-cycle alarms work?
Phones and watches estimate sleep stages from movement, sound or heart rate. That's an estimate, and less precise than a sleep lab. Many people still find that being woken at a lighter moment feels gentler. If you like the idea, it costs little to try.
Why planning matters more for most people
Waking a few minutes earlier in light sleep helps a little. Waking at the wrong time altogether, for the meeting you forgot or an hour early on a home day, costs far more. A planning alarm fixes that part. First Thing does both: it plans the time, and with Pro on a Wear OS watch it can buzz up to 20 minutes early if you're already stirring, never later.
An alarm that works out the time
First Thing reads your week and, if you like, your calendar, and sets one alarm with the reason beside it.
Questions
What is the best smart alarm app for Android?
For sleep tracking with a light-sleep wake-up, Sleep as Android. For an alarm that works out when you need to be up, First Thing. See our full comparison.
Do I need a watch for a smart alarm?
Not for a planning alarm. Sleep-cycle alarms can use your phone on the mattress, but a watch usually gives better readings.
Will a smart alarm ever wake me late?
It shouldn't. Sleep-cycle alarms wake you no later than the end of your window, and First Thing's smart wake is never later than your alarm.