Time is specified in two ways.
1. Ordinary time or \(12\)-Hour format
2. Railway time or \(24\)-Hour format
Ordinary Time or the 12-Hour Format:
  • A day has \(24\) hours. It is divided into two periods; each has \(12\) hours.
  • \(12\!:\!00\) at night is called midnight, and \(12\!:\!00\) at day is called noon.
  • The \(12\) hour clock has Ante Meridien (a.m.) and Post Meridien (p.m.).
  • Ante Meridien \(-\) Midnight \(12\!:\!00\) to Noon \(12\!:\!00\)
  • Post Meridien \(-\) Noon \(12\!:\!00\) to Midnight \(12\!:\!00\)
1. \(9\!:\!00\) a.m. means \(9\)'O clock in the morning (before noon).
2. \(9\!:\!00\) p.m. means \(9\)'O clock in the night (after noon).
Railway time or \(24\)-Hour format:
  • \(24\)-hour clock mostly followed in railways, airways and defence.
  • It is the clock from \(0\) hours to \(24\) hours.
  • \(24\)-hour time format usually has \(4\) digits. First, two digits are hours, and the last two digits are minutes.
  • We don't need to mention morning, noon, evening and night in the \(24\)-hour clock.
  • \(12\) at midnight is denoted as \(00\!:\!00\) hours.
1. \(2\!:\!00\) in the after noon \(=\) \(14\!:\!00\) hours
2. \(6\!:\!00\) in the evening \(=\) \(18\!:\!00\) hours
\(12\)-Hour format and \(24\)-Hour format:
24 hour format.png