TimeA numerical representation of what point in a day it is. Time is displayed in hours, followed by minutes, and then seconds. There are 24 hours in one day, 1,440 minutes in a one day, and 86,400 seconds in one day.


A hour may be represented by a numerical value of 1 to 12 or 0100 to 2400. Several digital clocks and computers running Microsoft Windows display civilian time using hours of 1 to 12 and represent the time of day with AM or PM. Many Unix, Linux, and other clocks may use military time, which has no AM or PM and uses hours of 1 to 24. Below is a listing of Military time values and their conversions to Civilian time.

Civilian Military Civilian Military
12 AM 2400 12 PM 1200
1 AM 0100 1 PM 1300
2 AM 0200 2 PM 1400
3 AM 0300 3 PM 1500
4 AM 0400 4 PM 1600
5 AM 0500 5 PM 1700
6 AM 0600 6 PM 1800
7 AM 0700 7 PM 1900
8 AM 0800 8 PM 2000
9 AM 0900 9 PM 2100
10 AM 1000 10 PM 2200
11 AM 1100 11 PM 2300

Minute and second

A minute is represented in numerical values of 00 to 59. There are 60 minutes in every hour and 60 seconds in every minute.

Time zones

The world is broken into 24 separate time zones that are used to help determine the time in all areas of the world. GMT (Greenwich Mean Time) or UT (Universal Time) is a method of referencing the time differences across the world. The GMT or UT is centered in the middle of the time zone as 12:00. Any time zone to the left of this is -GMT or -UT and any time zone to the right of this is +GMT or +UT. Below is a listing of time zone abbreviations, time zone descriptions, and the UT difference.

Time Zone Time Zone Description UT
ACDT Australia Central Daylight Time UT +10:30
ACST Australia Central Standard Time UT +9:30
ADT Atlantic Daylight Time UT-3:00
AKDT Alaskan Time Zone UT-9:00
AST Atlantic Standard Time UT-4:00
AT Azores Time UT-1:00
AWST Australia Western Standard Time UT+8:00
BST British Summer Time UT+1:00
BST Brazil Standard Time UT-3:00
BT Baghdad Time UT+6:00
BTT Bhutan Time UT+6:00
CAT Central Africa Time UT+2:00
CCT China Coast Time UT+8:00
CDT Central Daylight Time (USA) UT-5:00
CDT Central Daylight Time (Australia) UT+10:30
CEST Central Europe Summer Time UT+2:00
CET Central Europe Time UT+1:00
CKT Cook Islands Time UT-10:00
CLST Chile Summer Time UT-3:00
CLT Chile Time UT-4:00
COT Colombia Time UT-5:00
CST Central Standard Time (USA) UT-6:00
CST Central Standard Time (Australia) UT+9:30
CST China Time UT+8:00
CST Cuba Standard Time UT-4:00
CUT Coordinated Universal Time -
ECT Esuador Time UT-5:00
ECT Eastern Caribbean Time UT-4:00
EMT Norway Time UT+1:00
EST Eastern Standard Time (USA) UT-5:00
EST Eastern Standard Time (Australia) UT+10:00
EST Eastern Brazil Standard Time UT-3:00
FST French Summer Time UT-2:00
GMT Greenwich Mean Time -
GST Guam Standard Time UT+10:00
GST Gulf Standard Time UT+4:00
GST Greenland Standard Time UT-3:00
GT Greenwich Mean Time -
HFE Heure Francais d'Ete UT+2:00
HST Hawaiian Standard Time UT-10:00
ICT Indochina Time UT+7:00
IST Irish Summer Time UT+1:00
IST Israeli Standard Time UT+2:00
IST Iran Standard Time UT+3:30
IST Indian Standard Time UT+5:30
IT Iran Time UT+3:30
JST Japan Standard Time UT+9:00
KDT Korean Daylight Time UT+10:00
KST Korean Standard Time UT+9:00
LST Local Sidereal Time -
MDT Mountain Daylight Time (USA) UT-6:00
MST Mountain Standard Time UT -7:00
MPT North Mariana Islands Time UT+10:00
MSD Moscow Summer Time UT+4:00
MSK Moscow Time UT+3:00
MT Moluccas UT+8:30
MUT Mauritius Time UT+4:00
NST Newfoundland Time UT-3:30
NST North Sumatra Time UT+6:30
PDT Pacific Daylight Time (USA) UT-7:00
PMT Pierre and Miquelon Standard Time UT-3:00
PNT Pitcairn Time UT-8:30
PST Pacific Standard Time (USA) UT-8:00
PST Pakistan Standard Time UT+5:00
SST Swedish Summer Time UT+2:00
SST Singapore Standard Time UT+8:00
TMT Tukmenistan Time UT+5:00
TST Turkish Standard Time UT+3:00
UT Universal Time -
WST Western Standard Time (Australia) UT+8:00
WST Western Brazil Standard Time UT-4:00
WST West Samoa Time UT-11:00

Daylight saving time and summer time

Daylight Saving Time, or DST for short, is period of time where, in most parts of the United States and other parts of the world, time gains or loses an hour on a specific date. DST is still being used today as a means to help conserve energy. As of 2007, in the United States, DST is observed from the second Sunday in March until the first Sunday in November.

Other countries have a "summer time", but do not change their clock time. For example, the European Union observes "summer time" from the last Sunday in March to the last Sunday in October.

Additional questions related to time

At what point does time change from AM to PM?

AM changes to PM and PM changes to AM at the stroke of 12:00.

Also see: A.M., Access time, Connect time, Date, Deceleration time, Disk access time, Downtime, Epoch, Holdup time, Idle time, Link time, Measurement, NTP, P.M., Real-time, Recovery time, Response time, Run time, Seek time, Settling time, Tick, Time server, Time out, Time sharing, Time-slice, Time stamp, Timer, Transfer time, Universal time, Uptime