Convert Decimal (Person Days) to Time in Excel

: Joel Lipman; Excel; 13 February 2013; Hits: 6928

What?
We have an excel spreadsheet which reports against a mySQL database and reads time spent on projects by IT Service colleagues. The main report is a pivot table with staff members along the top, tasks down the first column, and time spent in the form of person days in the cross-join.

Why?
Currently the smallest bookable time by low-level tape monkeys and techies is 30 minutes (Managers it would appear can book whatever time, eg. 5mins). 30 minutes for us translates to 0.07 in person days (a person day being 7 hours and 24 minutes or 26640 seconds).

How?
The answer was always going to be a convoluted formula just to convert it into minutes and then format the resulting value into a custom format of [h]:mm:ss

copy raw

-- Aim / Objective:

ColumnA     ColumnB     ColumnC
----------  ----------  -----------
Task 1      0.14        1:00:00 
Task 2      0.07        0:30:00 
Task 3      4.80        34:15:00

-- Aim / Objective:
ColumnA ColumnB ColumnC
---------- ---------- -----------
Task 1 0.14 1:00:00
Task 2 0.07 0:30:00
Task 3 4.80 34:15:00

Excel needs the decimal number to be representative of a 24 hour slot. In other words, 1.0 in decimal, formatted to time is equal to 24 hours; 0.5 would be 12 hours and so forth. My formula:

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-- Given Cell B5 = 0.14 person days from above example.
-- 1 person day = 26640 seconds and 1440 minutes = 24 hours.
-- 0.07 person days = 30 minutes or 0.14 person days = 1 hour.

0.04166667 =(ROUND(B5/0.07, 0)*30)/1440       -- now format to [h]:mm:ss
-- yields 1:00:00

0.04166667 =(ROUND(B5/0.07, 0)*0.5)/24        -- now format to [h]:mm:ss
-- yields 1:00:00

-- Given Cell B5 = 0.14 person days from above example.
-- 1 person day = 26640 seconds and 1440 minutes = 24 hours.
-- 0.07 person days = 30 minutes or 0.14 person days = 1 hour.
0.04166667 =(ROUND(B5/0.07, 0)*30)/1440 -- now format to [h]:mm:ss
-- yields 1:00:00
0.04166667 =(ROUND(B5/0.07, 0)*0.5)/24 -- now format to [h]:mm:ss
-- yields 1:00:00

Note that the first formula is converting person days into minutes and then dividing by 1440 (resulting in the decimal number: 0.04166667 - 1 hour of a 24 hour slot or 1/24), you then right-click and format it to time and it should match the results above.

The second formula is converting person days into hours and then dividing by 24 (which should return the same decimal number).

Category: Excel :: Article: 486