Exact time, to the second

How the offset is measured

The site’s server constantly sets its clock against reference time servers using the NTP protocol. Your browser asks it for the time three times in a row, measuring each request’s round trip.

The fastest measurement is kept: the server time, corrected by half that round trip, is compared with your device’s time. The uncertainty shown (“±”) is that half round trip. It is a few hundredths of a second on a good connection and grows on a busy mobile network.

The time shown on this site is always corrected for the measured offset, even if your device is fast or slow.

Setting your device’s clock

Computers and phones set themselves when automatic time is turned on. If your clock drifts, force a new synchronisation:

Windows

1. Open Settings (Windows key + I).
2. Go to Time & language, then Date & time.
3. Click “Sync now”.

macOS

1. Open System Settings.
2. Go to General, then Date & Time.
3. Turn “Set time and date automatically” off and on again.

Linux

In the Date & Time settings, turn automatic time back on, or in a terminal: timedatectl set-ntp true.

iPhone and iPad

1. Open Settings, then General, then Date & Time.
2. Turn “Set Automatically” off and on again.

Android

1. Open Settings, then System, then Date & time.
2. Turn “Set time automatically” off and on again. Labels vary between manufacturers.