Set the alarm clock for 5:15 am

How to use the online alarm clock

Setting an alarm for 5:15 am while everyone else is asleep can feel like cheating the clock, but it's usually just planning ahead for an early departure or a shift that starts before sunrise. This will sound at 5:15 am through your speakers, whether it's the depths of winter or a short summer night.

Choose a sound before you press Start — something like a chime or a classic bell tends to work better than anything too gentle. Once it's running, the countdown happens right here in the browser, which means the tab needs to stay open in the background rather than being closed.

Unlike a phone alarm, this one won't ring if you close the tab, put the computer to sleep, or shut the lid, so it suits a desk, a kitchen bench, or anywhere the device stays powered on and awake. It's free to use and doesn't need an account, but it's not built for unattended overnight use. On a 24-hour clock 5:15 am is written 05:15, and spoken aloud it's quarter past five in the morning. Timetables and rosters may show it as 05:15, and handwritten notes as 5.15 am. Setting the alarm to 5:15 am tomorrow morning works the same way: if the time has gone for today, the count runs through to it.