⌚ Watch Accuracy Tester

Free online Watch Accuracy Tester. Easily check how accurate your mechanical or quartz watch is by measuring seconds gained or lost per day (s/d). Works for Rolex, Seiko, Omega, Citizen, Apple Watch and any other timepiece. Completely private – all data stays on your device.

How the Watch Accuracy Tester Works

This free tool helps you measure the real-world accuracy of your watch in seconds per day. It is the same method used by watchmakers and collectors to test timekeeping performance.

  1. Synchronize your watch with the exact time shown on this page.
  2. Start the test and wait several hours or days.
  3. Come back, enter how many seconds your watch is fast or slow, and get the accurate rate in s/day.

Current Test

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Start New Accuracy Test

  1. Set your watch to the exact same time as this page (to the second).
  2. Click Start Test.
  3. Come back after several hours or days and click Finish.

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Frequently Asked Questions

What is a good watch accuracy?
Most mechanical watches are considered good between -10 to +20 seconds per day. High-end chronometers are often -4 to +6 s/day. Quartz watches are usually within ±1 to ±3 s/day.

How long should I run the test?
For best results run the test for at least 12–24 hours. Longer tests (2–7 days) give more accurate average rates.

Does this work for smartwatches and quartz watches?
Yes. The Watch Accuracy Tester works with mechanical, automatic, quartz, and smartwatches.

Is my data private?
Yes. Everything is stored only in your browser (localStorage). Nothing is sent to any server.

Watch Accuracy Tester · Measures seconds per day (s/d) · Data stays only on your device