Lessons · Nursing · hours, minutes and the 24-hour clock
Hours, minutes and the 24-hour clock
One hour is 60 minutes. Pumps and orders speak in hours; drips, piggybacks and boluses speak in minutes; and the clock on the chart runs from 0000 to 2359 with no am or pm.
Hone is a place to practise a career, one idea a day. This is one of its lessons, written out in full and free to read without an account.
What it is for
An antibiotic is ordered over 30 minutes and the pump wants a rate per hour. A dose is due at 1400 and the chart says it was given at 0200. Half of every rate problem is a time conversion, and a twelve-hour mistake on the clock is a missed dose or a double one.
How to think about it
Minutes to hours: divide by 60. Hours to minutes: multiply by 60. On the 24-hour clock, anything after noon has twelve added: 2:30 pm is 1430. To find how long between two times, subtract the hours and then the minutes, borrowing sixty when you need to.
Worked example
1.5 h = 1.5 × 60 = 90 minHours to minutes: multiply by sixty.
45 min = 45 / 60 = 0.75 hMinutes to hours: divide by sixty. Three quarters of an hour.
2:30 pm = 1430; 9:15 am = 0915After noon, add twelve to the hour. Morning times keep their hour and gain a leading zero.
0600 to 1400 = 8 hFourteen minus six. A day shift's worth of an infusion.
Your turn
Write 2.5 hours in minutes.
2.5 × 60 = min
Solve one, graded on the server
The trap
Writing 4:00 pm as 0400. Afternoon hours add twelve: 1600. A medication charted at 0400 that was given at 1600 is a twelve-hour error on paper, and the next nurse works from the paper.