Binary clock

A binary clock shows each part of the time as lit and unlit lights. In binary-coded decimal (BCD) mode each digit gets its own column; in pure binary mode hours, minutes and seconds are each one binary number.

Turn on the decimal digits while you learn to read it, then turn them off to impress your friends.

Customise the binary clock

• Background
• On
• Off
• Encoding
• Shape
• Show decimal digits
• Glow

How to use

• Switch clocks with ← →, by clicking or tapping the sides of the screen, or by swiping. The dice button (R) jumps to a random clock.
• Go full screen with the button in the top-right corner, a double-click or F.
• Open Customise (S) to change colours, fonts, 12/24-hour time, seconds, date and time zone. Settings are saved on this device.

Questions

How do I read a binary clock?

From the bottom, the lights in each column are worth 1, 2, 4 and 8. Add up the lit ones to get that digit. For example, lit 4 and 2 make 6.

More clocks

ClockFaces · Free online clocks