Hexadecimal time

Nystrom's "Tonal Watch, or Clock-dial". Note the use of his invented digits for hex values 9-F. Also note that midnight (hour 0) is at the bottom, rather than the top of the clockface.

A hexadecimal clock-face

Hexadecimal time is the representation of the time of day as a hexadecimal number in the interval [0,1).

The day is divided into 10₁₆ (16₁₀) hexadecimal hours, each hour into 100₁₆ (256₁₀) hexadecimal minutes, and each minute into 10₁₆ (16₁₀) hexadecimal seconds.

History

Hexadecimal time may have been used during the Tang Dynasty (7th-10th centuries) in China.

This time format was proposed by the Swedish-American engineer John W. Nystrom in 1863 as part of his tonal system.

In 1997, the American Mark Vincent Rogers of Intuitor proposed a similar system of hexadecimal time and implemented it in JavaScript as the Hexclock.

The system of Rogers

A day is unity, or 1, and any fraction thereof can be shown with digits to the right of the hexadecimal separator.
So the day begins at midnight with .0000 and one hexadecimal second after midnight is .0001.
Noon is .8000 (one half), one hexadecimal second before was .7FFF and one hexadecimal second before next midnight will be .FFFF.

Intuitor-hextime may also be formatted with an underscore separating hexadecimal hours, minutes and seconds. For example:

Clock

Hex	Hex (Boardman)	ISO 8601	Comment
.0100	0_10_0	00:05:37.5
.0200	0_20_0	00:11:15
.0400	0_40_0	00:22:30
.0800	0_80_0	00:45:00
.1000	1_00_0	01:30:00	1.5:24 = 1:16 = 0.1
.8000	8_00_0	12:00:00	12:24 = 8:16 = 0.8
.F000	F_00_0	22:30:00	22.5:24 = 15:16 = 0.F
.F800	F_80_0	23:15:00

Conversions

Hex		hexsec base 16		hexsec base 10		Traditional
1 day	=	10000	=	65536	=	24 h
1 hexadecimal hour	=	1000	=	4096	=	1 h 30 min
1 hexadecimal maxime	=	100	=	256	=	5 min 37.5 sec
1 hexadecimal minute	=	10	=	16	=	21.09375 sec
1 hexadecimal second	=	1	=	1	=	1.318359375 sec
1 second	=	0.C22E4	=	0.75851	=	1 sec

See also

• Decimal time
• Metric time

References

External links

• Hexadecimal Time Applet - with digital and analogue representations.
• Hexclock - local time as a hexadecimal number
• True Binary Time - local time as a binary number
• Analogue hexadecimal clock - Florence Mean Time
• Geektime.org - different approach, based on "hex-seconds"