Clock Tools
Timer, stopwatch, alarm, Pomodoro, chess clock, world clock, and more — all running in your browser.
No alarms set. Choose a time and click Set Alarm.
Calculate optimal bedtimes based on 90-minute sleep cycles. Waking at the end of a cycle helps you feel more refreshed.
10 Clock Tools in One Page
This page combines ten of the most commonly searched online clock tools into a single, fast-loading interface. Every tool runs entirely in your browser — no data leaves your device, no server calls, no installs.
Countdown Timer with Presets
The countdown timer includes twelve one-click presets covering the most common durations people search for: 1 minute, 3 minutes, 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes (Pomodoro), 30 minutes, 45 minutes, 60 minutes, 90 minutes, and 2 hours. Each preset is labeled with its most popular use case so you can tap and go. You can also enter any custom duration using the hour, minute, and second fields.
Stopwatch with Lap Times
A precise stopwatch measuring to hundredths of a second. Start, stop, and record lap splits to track individual segment times. The lap list shows both the split time for each lap and the cumulative elapsed time, making it useful for tracking splits during runs, workouts, or lab experiments.
Online Alarm Clock
Set one or more alarms by choosing a time and an optional label. The alarm uses your browser's built-in audio to alert you when the time is reached. Set multiple alarms for different reminders throughout the day. The alarm will sound as long as the browser tab stays open.
Pomodoro Timer
Follows the standard Pomodoro Technique: 25 minutes of focused work followed by a 5-minute break. After four work sessions, a longer 15-minute break begins automatically. The dot indicators show your progress through each four-session cycle.
Chess Clock
A two-player chess clock with configurable starting time and increment per move. Tap or click your side of the board to pass control to your opponent. Supports Fischer-style increment (seconds added after each move). The active player's side highlights, and the display turns red when time is running low.
World Clock
Add multiple time zones from a list of 20 major cities spanning the Americas, Europe, Asia, and Oceania. Each clock updates live and shows the current time, date, and UTC offset. Useful for scheduling meetings across different regions or tracking international event times.
Count Up Timer
Measures elapsed time from zero upward. Start it when an event begins — a meeting, a cooking process, or a parking meter — and stop it whenever you need to see how much time has passed. Displays hours, minutes, and seconds.
Interval Timer (HIIT / Workout)
Designed for high-intensity interval training, circuit workouts, Tabata, or any activity that alternates between work and rest periods. Configure your work duration, rest duration, number of rounds, and an optional preparation countdown. The display shows the current phase (work or rest), the round number, and a progress bar for each interval.
Sleep Calculator
Uses the 90-minute sleep cycle model to suggest optimal bedtimes or wake times. Choose whether you want to wake up at a specific time or go to sleep at a specific time, and the calculator shows six options ranging from three to six full sleep cycles, plus a 15-minute buffer to account for falling asleep.
Unix Timestamp Converter
Displays the current Unix epoch timestamp updating in real time, along with the corresponding human-readable date. Convert any Unix timestamp to a readable date, or convert any date and time to its Unix timestamp equivalent. Widely used for debugging APIs, working with databases, and handling date values in programming.
Frequently Asked Questions
Does the online alarm clock work if I close the browser?
No. The alarm runs inside your browser tab using JavaScript. If you close the tab or the browser, the alarm stops. Keep the tab open and your computer awake for the alarm to sound at the set time.
Does the online timer work without internet after the page loads?
Yes. Once the page is loaded, all clock tools run entirely in your browser using JavaScript. No server connection is needed to keep the timer, stopwatch, or alarm running.
What is a Pomodoro timer and how does it work?
A Pomodoro timer uses the Pomodoro Technique: you work for 25 minutes, then take a 5-minute break. After four work sessions, you take a longer 15-minute break. This cycle helps maintain focus and prevent burnout during study or work sessions.
How does the chess clock work for two players?
Each player starts with the same amount of time. Press your side button to start your opponent clock and stop yours. Optional increment adds seconds after each move. When a player time reaches zero, they lose on time.
What is a Unix timestamp and why is it used?
A Unix timestamp is the number of seconds elapsed since January 1, 1970 at 00:00:00 UTC. It is widely used in computing for date storage, API requests, and database records because it represents any moment in time as a single integer.
How does the sleep calculator determine the best bedtime?
The sleep calculator works on 90-minute sleep cycles. It counts backward from your desired wake time in 90-minute increments, plus a 15-minute buffer to fall asleep. Waking at the end of a cycle helps you feel more refreshed.
What is an interval timer used for?
An interval timer alternates between work and rest periods in repeated rounds. It is commonly used for HIIT workouts, circuit training, Tabata, and any exercise routine that requires timed sets with fixed rest periods.
Can I use the stopwatch to record lap times?
Yes. The stopwatch includes a lap feature. Click or tap the Lap button while the stopwatch is running to record the current elapsed time. All laps show individual split times and cumulative times.