Alarm clock
Enter alarm times (one HH:MM per line, optional note) plus the current time, and get the minutes until each alarm, whether it lands tomorrow, and a sleep-length estimate — all computed locally without timers or notification permission.
Runs in your browserEvery computation happens in your browser — your data never leaves this device.
Ring plan
Sorted by time remaining.
Enter alarm times and the current time to plan
Alarms: 0 · Next ring (min): 0 · Sleep (min): 0
What this tool does
- Line up wake-up and break reminders before bed and see the countdown.
- Check whether each alarm lands today or tomorrow.
- Estimate sleep length from a bedtime.
Example
Input
07:30 wake up 09:00 12:30 nap
Output
当前时间 / Now: 22:15（提前 5 分钟提醒） 闹钟列表 / Alarms: 07:30 wake up → 次日 07:25（550 分钟后响铃，响 30 秒） 09:00 (无备注) → 次日 08:55（640 分钟后响铃，响 30 秒） 12:30 nap → 次日 12:25（850 分钟后响铃，响 30 秒）
You provide the current time: the tool never reads the system clock and registers no timers, so the remaining minutes are deterministic.
Frequently asked questions
Why does it not actually ring with a browser timer?
Background tabs get throttled, so timers drift. This tool focuses on computing the next ring time; use your system alarm for an audible wake-up.
How is the next day detected?
If the alarm time minus the lead time is earlier than the current time, the alarm is treated as tomorrow and labelled accordingly.
How is sleep length computed?
From the bedtime you enter to the nearest alarm, rolling over midnight when needed.
Can an alarm carry a note?
Yes. Write it as "07:30 wake up": the text after the time becomes the note and appears verbatim in the result.
Keywords：在线闹钟alarm定时提醒闹钟时间睡眠时长起床时间next alarm