Clock Drift Checker
Compare your device clock with this site's UTC time and review the browser and estimated network TimeZones.
Only when you select "Check" does this page connect to api/time .
This is a same-site time API; no input data is transmitted.
Status
Unconfirmed
Device time
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Browser TimeZone
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Estimated network TimeZone
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Round-trip time
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Judgment result
UnconfirmedMeasurement criteria
- Clock drift is calculated by comparing the device time with this site's UTC time API or HTTP Date header. Network delay is approximated as half the round-trip time.
- Both the estimated network TimeZone and browser TimeZone are shown because the network estimate may be inaccurate when a VPN or proxy is in use.
- A drift of up to 2 seconds is treated as normal, up to 30 seconds as a warning, and more than 30 seconds as requiring attention.
- Accurate clock drift cannot be calculated while completely offline or when an HTTP Date header cannot be obtained. In that case, only the device time and browser TimeZone are shown.
About this tool
You can check how far the clock on your PC or smartphone deviates from the standard time.
Features
- Comparison of device time with this site's UTC time
- Browser and estimated network TimeZone display
How to use
- Press Check to retrieve the reference time.
- Review the clock drift calculated from multiple requests.
- Review your device's automatic time settings if necessary.
Limitations
- Even if communication delays are corrected, the measured values will still contain errors.
- This site's API is used as the time reference instead of an external time service.
Privacy: Clock measurement connects to this site's UTC time API. No input data is sent to a third-party service.