The free Exact Time & Clock Accuracy Check
Show the exact current time to the millisecond and check how far your computer or phone clock is off. NTP-style sync with a server, plus UTC, Unix time.
- Free to use
- No signup
- Nothing to install
- Works in any modern browser
Your clock is 2.31 seconds fast → your 2FA codes may fail and meetings show odd times. Within ±40 ms → accurate.Open the Exact Time & Clock Accuracy Check
Illustration. Open the tool for the real thing.
See it in action
Shown running with its default sample values
What is the Exact Time & Clock Accuracy Check?
Wrong clocks cause failed logins with two-factor codes, expired-certificate errors, broken meetings and confusing file dates. This tool shows the exact time to the millisecond and tells you how far your device clock is fast or slow.
It works like NTP: the page asks our server for its time nine times, measures how long each round trip takes, assumes the reply spent half of that in each direction and uses the fastest sample to calculate the offset. You get a live corrected clock, your clock's error and the accuracy of the measurement, plus UTC time, ISO 8601, Unix timestamps, day of year, ISO week number and leap-year status, all corrected to the true time.
3 steps to your result
Open the tool and follow along. Nothing to install.
What you get
A live clock corrected against the server.
How fast or slow you are, with ± accuracy shown.
UTC, ISO 8601, Unix seconds and milliseconds.
Repeats every two minutes to stay accurate.
AZRS tools are free to open and use.
It opens in your browser, so there is nothing to download.
Used for
Pick one to see how it fits.
How it compares
A plain look at this tool next to the usual alternative.
| This utility | Desktop software | |
|---|---|---|
| Install | Nothing to install | Usually an app or program to install |
| Account | No signup | Depends on the product |
| Cost | Free to use | Free or paid, depends on the product |
Questions people ask
How do you know the true time?
We compare with our server's clock, which is kept in sync by network time protocol. Accuracy is roughly half your round-trip time plus the server's own tiny error.
How accurate is this?
Usually within tens of milliseconds on a good connection, shown as ± under Sync accuracy.
Why does 2FA fail with a wrong clock?
One-time codes are computed from the current time, so a clock more than about 30 seconds off produces invalid codes.
How do I fix a wrong clock?
Enable automatic time in your operating-system date and time settings and choose the right time zone.
What is a Unix timestamp?
The number of seconds (or milliseconds) since 1 January 1970 UTC.
More free tools
Related to the Exact Time & Clock Accuracy Check.
Try the Exact Time & Clock Accuracy Check now
See the exact time and how many milliseconds your device clock is off. Free to use.
Try it free