aceclock Open the clock

Online Clock

A big, accurate digital clock showing the current time and date — free, full-screen ready, no download.

  • Free
  • No signup
  • Works offline
  • Instant

More on aceclock

Analog Clock Analog A clean analog clock with hour, minute and second hands. Stopwatch Stopwatch Start, stop and lap a precise stopwatch right in your browser. Countdown Timer Timer Set a countdown timer with an alarm — perfect for cooking, workouts and study.

aceclock.com is a tidy set of everyday time tools: a big online clock showing the current time, a classic analog clock, a precise stopwatch, and a countdown timer with an alarm. Everything runs in your browser — no app, no signup.

Time, at a glance

Keep the clock open as a desk or presentation clock, lap a workout on the stopwatch, or set the timer for cooking and focus sessions. Below, our guides cover time zones, telling time, and getting the most from each tool.

From our guides

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Telling time Why 60 Minutes in an Hour and 24 Hours in a Day? The 24-hour day and 60-minute hour come from ancient Egyptian and Babylonian number systems, not from a single plan. 4 min read Clocks explained A Short History of Clocks: Sundials to Atomic Time From ancient sundials to atomic clocks, discover the key inventions that shaped how we measure time. 5 min read Telling time How to Teach a Child to Tell Time, Step by Step Learn how to teach a child to tell time with a clear step by step sequence: o'clock, half past, quarter past, quarter to, and five minute intervals. 5 min read Productivity & focus The 52/17 Rule and Other Focus-Break Timer Ratios Compare work/break ratios beyond Pomodoro, including the 52/17 rule, 90-minute focus sessions, and 50/10, and learn how to set each on a timer. 3 min read Stopwatch & timer tips Hand Timing vs Electronic Timing: How Accurate Is a Stopwatch? Hand timing with a stopwatch introduces human reaction error of 0.2 to 0.25 seconds, but you can reduce it with simple techniques. 4 min read Clocks explained Why Clock Faces Use IIII Instead of IV for Four Many clock and watch dials use IIII instead of IV for four. This article explores the common explanations for the watchmaker's four. 3 min read Clocks explained Why Do Clocks Run Clockwise? The Sundial Origin Learn why clocks turn clockwise, from the sundial shadow direction origin in the Northern Hemisphere to counterclockwise clock novelties. 4 min read Telling time 12 AM or 12 PM? Midnight, Noon and What A.M. Means Learn once and for all: 12 AM is midnight, 12 PM is noon, and why the Latin meanings of ante meridiem and post meridiem make it that way. 3 min read

Frequently asked questions

Is aceclock.com free?
Yes — every tool is free, with no signup and no download.
Does it work on my phone?
Yes — it works in any modern browser on phones, tablets and computers.
Is the time accurate?
It shows your device's time, which is normally network-synced, so it's as accurate as your device's clock.