Online Alarm Clock - Free Browser Wake Up Alarm

Quick alarm presets

Click any time below to set an alarm for the next time it comes around. The new alarm appears in the list at the top of the page with the toggle switched on. AM presets are labelled "Wake up", PM presets "Bedtime" - you can rename either via the Edit button on the alarm card.

Wake-up alarms (AM)

Bedtime & evening alarms (PM)

Need a different time? Tap Set alarm at the top to enter any HH:MM AM/PM you want. Looking for an alarm a few minutes from now (e.g. "in 5 minutes")? That's a countdown - use our online timer instead.

Key features

• Unlimited alarms: Keep as many alarms as you want. Each is independent with its own time, label, sound and on/off switch.
• Custom labels: Name every alarm ("Wake up", "Standup", "Take meds", "Pick up kids") so you know exactly what is ringing at a glance, even when several fire in the same hour.
• 6 alarm tones: Radar, Beacon, Chime, Digital, Gentle and Classic - generated with the browser's Web Audio API so they load instantly. A short preview plays when you pick one.
• 12-hour format with AM/PM: A single tap toggles AM or PM, matching the way most people actually read the clock.
• Per-alarm toggle switch: Pause an alarm for the week without deleting it - flip the switch back on when you need it again.
• Live current clock: The actual time and date sit at the top of the page so you can compare them to the alarms below.
• "Rings in" countdown: Every enabled alarm card tells you how many hours and minutes are left until it fires.
• Merged ring for same-minute alarms: If two or more alarms share the same minute, they ring together in a single overlay with every label stacked so you don't miss any.
• Auto-stop after 5 minutes: If nobody is at the keyboard, the ring stops itself instead of blaring forever.
• Tab title flash: While the alarm rings, the browser tab flashes 🔔 HH:MM AM/PM so you can spot it even if the tab is pinned in the background.
• Saved locally: Alarms persist in your browser's localStorage - nothing is sent to a server and no account is required.
• 8 theme colors: Dark, Light, Red, Teal, Blue, Purple, Green, Slate. The alarm clock matches the rest of stopwatch-online.com.
• Works offline: Once the page is loaded, the alarm runs entirely in your browser - no connection needed.

How to set an alarm

Step 1: Open the alarm editor

Click Set alarm. A modal opens with a new alarm pre-filled for the next whole hour (e.g. if it's 2:47 PM, the picker starts at 3:00 PM) so setting a "next hour" alarm is almost zero-effort.

Step 2: Pick the time

On desktop, click the hours or minutes digits and type from your keyboard - typing two digits auto-advances from hours to minutes. On mobile, tap a field to open a scrollable picker. Tap AM / PM to flip between morning and afternoon.

Step 3: Add a label (optional)

Write a short note so future-you knows why this alarm exists - "Wake up", "Meeting at 3", "Move laundry", "Take the bread out", "Log off". Labels are also shown on the ring overlay when the alarm fires.

Step 4: Pick an alarm sound

Open the Sound selector and choose one of the six tones. A short preview plays immediately so you know exactly what you'll hear. The last sound you used is remembered as the default for your next alarm.

Step 5: Save and keep the tab open

Press Save. The alarm card appears in the list with a "Rings in Xh Ym" countdown. Keep the browser tab open - pin the tab (right-click the tab → Pin) to keep it out of the way without closing it.

Edit, toggle or delete

Every alarm card has a toggle switch on the right and two buttons underneath. Toggle to pause without losing the alarm, Edit to change the time, label or sound, Delete to remove it for good. Toggling or deleting animates the list smoothly so you never lose your place.

Keyboard shortcuts (desktop)

Inside the alarm editor:

• 0-9 - Type the hour or minute value directly
• Tab - Move from the hour field to the minute field
• Backspace - Reset the active field (hour → 12, minute → 00)
• Enter - Save the alarm
• Esc - Close the editor without saving

When an alarm is ringing:

• Space or Esc - Dismiss the alarm and silence the sound

When to use an online alarm clock

Wake-up alarm on a laptop

If you fell asleep with your phone in the other room (or with the ringer off by mistake), a browser alarm on the laptop next to the bed is a solid backup. Pick a loud tone like Radar or Digital, set a label ("WAKE UP"), and keep the laptop plugged in so it doesn't sleep before the alarm fires.

Short naps & power naps

A 20-minute nap alarm without reaching for your phone - click the time 20 minutes from now, pick the Gentle or Chime tone, save. NASA's classic nap research points to ~26 minutes as the sweet spot; either way, an online alarm is faster to set than most phone alarm apps.

Work-from-home reminders

Set one alarm for "Stand up" every two hours, another for "Drink water" at 10 and 15, another for "Pack up for standup". Because each alarm has its own label and switch, you can pause the reminder ones over the weekend without losing the schedule.

Meeting prep

Fire an alarm 5-10 minutes before a call so you aren't caught mid-task when it starts. Label it with the meeting name ("Eng sync", "1:1 Sarah", "Client demo") and the ring overlay tells you exactly which call to join.

Cooking long, slow dishes

Slow cookers, braises, overnight doughs and proofing bread all want a check-in hours later. Set an alarm for the moment you need to stir, flip or rotate - the tab can live on a kitchen tablet the whole time. For short countdowns (pasta, eggs, steeping tea), use the online timer instead.

Shared or public computers

On a shared computer, library machine or work laptop where you can't sync a personal phone, a browser alarm is a quick, account-free way to get a reminder at a specific clock time. Nothing is stored server-side; your alarms live in that browser only.

Medication & routine reminders

Pair a label like "Take meds" or "Eye drops" with the Chime tone for a soft, non-startling reminder at the same time every day. Remember: each alarm rings once and then turns itself off - flip the switch back on the next morning if you want it again.

Presentations, classes & live events

Set an alarm for the end of a talk segment, a Q&A cut-off, or the transition between activities. Because the alarm is tied to a wall-clock time (not a duration), you can run it alongside a timer without either getting confused.

Alarm clock vs timer vs stopwatch: which do I need?

All three tools measure time, but they answer different questions:

• An alarm clock fires at a specific wall-clock time (e.g. 7:00 AM). Use it when you'd phrase the task as "Wake me at 7" or "Remind me at 2:45 PM".
• A countdown timer counts down from a duration (e.g. 15 minutes). Use it when you'd phrase the task as "Tell me when 15 minutes are up" - cooking, Pomodoro, workout intervals, tea steeping.
• A stopwatch counts up from zero. Use it when you don't know how long something will take and want to measure the result - a run, a cube solve, a puzzle.

Rule of thumb: if the answer involves a clock face (7:00 AM, 2:45 PM), use the alarm. If it involves a duration (15 min, 1 hour), use the timer. If it's measuring how long something actually took, use the stopwatch.

How the alarm clock works under the hood

Every alarm is stored with the absolute wall-clock timestamp of its next fire (not a duration), so the browser doesn't have to keep counting down. Once per second, the page asks "has that timestamp passed yet?" and rings if so.

• Alarms are saved in localStorage, which survives reloads and browser restarts - but not the full browser shutting down on a mobile device.
• When you return to a backgrounded tab, a visibilitychange handler re-reads the current time and rolls any missed alarms forward to the next day, so you don't get a stale ring from yesterday.
• Two or more alarms set to the same minute are deliberately collapsed into one ring - the overlay shows every label stacked, plays a single sound, and dismisses both in one click.
• Sounds are synthesized on the fly with the Web Audio API rather than loaded as MP3s, so the alarm works the instant the page opens and doesn't need a network connection to ring.
• The ring auto-stops after 5 minutes of no interaction so a forgotten laptop doesn't scream forever.

Tips & tricks

• Pin the tab. Right-click the tab → Pin tab. Pinned tabs are smaller, harder to close by mistake, and usually stay alive through full browser restarts in Chrome and Edge.
• Keep the laptop awake. Web alarms can't wake a sleeping computer. If you rely on a laptop alarm overnight, disable sleep (macOS: Prevent automatic sleeping on power adapter; Windows: Screen & sleep → Never) and keep it plugged in.
• Use descriptive labels. "Alarm" is useless at 2 AM; "Take the bread out" is not. The label appears on the ring overlay so you know instantly why you're being woken.
• Stack alarms to the same minute. If three things should happen at 3:00 PM, set three alarms labeled individually. They'll all ring together and you'll see every reminder on one screen.
• Test the sound first. Before relying on a new tone for wake-up, set an alarm for one minute from now and make sure the ringer is audible from where you'll be.
• Toggle instead of delete. If you use the same alarm on weekdays, keep it in the list and just toggle it off for the weekend - re-enabling takes one tap.
• Match the tone to the purpose. Radar and Digital are loud and attention-grabbing; Gentle, Chime and Beacon are softer and better for meds or meditation reminders.

Frequently asked questions