Subtract minutes in 15 min. increments

[raindrop]

Subtract minutes in 15 min. increments in MS. Excel 2007

Does anyone know how to subtract time in 15 min. increments. I am searching how to use time, but haven't quite figured it out.

What I am trying:
I put in a time and I need to subtract 15 min. from it. For example. I add the time of 1500 hard coded in cell C 48. Then I need to subtract time from it going to cell B4. Currently in Cell B I have a block of numbers (not in time format) of 15 min. increments for ex: C48 = 0 and time = 1500 then I need cell C45 to say 1445 and B45 to say 15.

Ex:
Column B Column C
<TABLE style="WIDTH: 141pt; BORDER-COLLAPSE: collapse" cellSpacing=0 cellPadding=0 width=187 border=0><COLGROUP><COL style="WIDTH: 55pt; mso-width-source: userset; mso-width-alt: 2669" width=73><COL style="WIDTH: 86pt; mso-width-source: userset; mso-width-alt: 4169" width=114><TBODY><TR style="HEIGHT: 18.75pt" height=25><TD class=xl63 style="BORDER-RIGHT: #e0dfe3; BORDER-TOP: #e0dfe3; FONT-WEIGHT: 700; FONT-SIZE: 14pt; BACKGROUND: #dbe5f1; BORDER-LEFT: #e0dfe3; WIDTH: 55pt; COLOR: #0070c0; BORDER-BOTTOM: #e0dfe3; FONT-FAMILY: Calibri; HEIGHT: 18.75pt; TEXT-DECORATION: none; text-underline-style: none; text-line-through: none; mso-pattern: black none" width=73 height=25>60</TD><TD class=xl65 style="BORDER-RIGHT: #e0dfe3; BORDER-TOP: #e0dfe3; FONT-WEIGHT: 700; FONT-SIZE: 11pt; BACKGROUND: #dbe5f1; BORDER-LEFT: #e0dfe3; WIDTH: 86pt; COLOR: #0070c0; BORDER-BOTTOM: #e0dfe3; FONT-FAMILY: Verdana; TEXT-DECORATION: none; text-underline-style: none; text-line-through: none; mso-pattern: black none" width=114>1400</TD></TR><TR style="HEIGHT: 18.75pt" height=25><TD class=xl63 style="BORDER-RIGHT: #e0dfe3; BORDER-TOP: #e0dfe3; BORDER-LEFT: #e0dfe3; BORDER-BOTTOM: #e0dfe3; HEIGHT: 18.75pt; BACKGROUND-COLOR: transparent" height=25>45</TD><TD class=xl65 style="BORDER-RIGHT: #e0dfe3; BORDER-TOP: #e0dfe3; BORDER-LEFT: #e0dfe3; BORDER-BOTTOM: #e0dfe3; BACKGROUND-COLOR: transparent">1425</TD></TR><TR style="HEIGHT: 18.75pt" height=25><TD class=xl63 style="BORDER-RIGHT: #e0dfe3; BORDER-TOP: #e0dfe3; BORDER-LEFT: #e0dfe3; BORDER-BOTTOM: #e0dfe3; HEIGHT: 18.75pt; BACKGROUND-COLOR: transparent" height=25>30</TD><TD class=xl65 style="BORDER-RIGHT: #e0dfe3; BORDER-TOP: #e0dfe3; BORDER-LEFT: #e0dfe3; BORDER-BOTTOM: #e0dfe3; BACKGROUND-COLOR: transparent">1450</TD></TR><TR style="HEIGHT: 19.5pt" height=26><TD class=xl63 style="BORDER-RIGHT: #e0dfe3; BORDER-TOP: #e0dfe3; BORDER-LEFT: #e0dfe3; BORDER-BOTTOM: #e0dfe3; HEIGHT: 19.5pt; BACKGROUND-COLOR: transparent" height=26>15</TD><TD class=xl65 style="BORDER-RIGHT: #e0dfe3; BORDER-TOP: #e0dfe3; BORDER-LEFT: #e0dfe3; BORDER-BOTTOM: #e0dfe3; BACKGROUND-COLOR: transparent">1475</TD></TR><TR style="HEIGHT: 24pt" height=32><TD class=xl66 style="BORDER-RIGHT: #e0dfe3; BORDER-TOP: windowtext 1pt solid; FONT-WEIGHT: 700; FONT-SIZE: 18pt; BACKGROUND: #dbe5f1; BORDER-LEFT: #e0dfe3; COLOR: #0070c0; BORDER-BOTTOM: windowtext 1pt solid; FONT-FAMILY: Calibri; HEIGHT: 24pt; TEXT-DECORATION: none; text-underline-style: none; text-line-through: none; mso-pattern: black none" height=32>0</TD><TD class=xl67 style="BORDER-RIGHT: windowtext 1pt solid; BORDER-TOP: windowtext 1pt solid; FONT-WEIGHT: 700; FONT-SIZE: 18pt; BACKGROUND: #dbe5f1; BORDER-LEFT: #e0dfe3; COLOR: #0070c0; BORDER-BOTTOM: windowtext 1pt solid; FONT-FAMILY: Calibri; TEXT-DECORATION: none; text-underline-style: none; text-line-through: none; mso-pattern: black none">1500</TD></TR></TBODY></TABLE>ROWs: 40 to 44

Any thoughts?

Thanks.

 

[GBagley]

Excel does time (as values) in increments of days (1 full day would = 1). To get minutes, you do 1 / 1440 (there are 1440 minutes in a day). So for 15 minutes, you would do =((1/1440)*15)

What is your unit of measurement for time? So when you have a time of 1500 hardcoded into a cell, is that 15:00 (3PM), or something else?