Man-hour is a measure of total hours worked by an average worker in one hour, used to estimate labor requirements for tasks and assess health and safety performance. The document outlines how to calculate man-hours using formulas based on total working hours, number of workers, and days worked, with examples for different organizations. Significantly, it emphasizes that calculating man-hours helps understand the impact of staff changes on task completion time.

1. BY ATUEYI CHIMA

2. WHAT IS MAN-HOUR?
Man hour is the total hour worked over a specific period of time or the
amount of work performed by the average worker in one hour. It is used for
estimation of the total amount of uninterrupted labor required to perform a
task.
Man hour is an integral factor in measuring Health and safety performance.
An organization that records 5 LTI in every 10,000 man-hour every 3 months
and the organization that record 10 LTI in every 100,000 man-hour every 3
month poses different Health and safety performance level. Judging by the
man-hour and the LTI recorded, the second organization has a better Health
and Safety performance.
Man-hours exclude the breaks that people generally require from work, e.g.
for rest, eating, and other bodily functions or public holidays. They count only
pure labor.

3. How To Calculate Man Hours
• Man hours formula = Total hours work a day per worker x
Total number of workers x Total numbers of days worked over
the specific period of time
• For a day: Total hours work a day per worker x Total
number of workers
Consider that:
Number of hours worked a day per worker: 8 hours
Total number of workers: 20 workers
Man Hour A day = 8 x 20
= 160 Man Hour.

4. • Calculating Man Hours Per Month
• Mathematically, having in mind the formular for calculating man hour.
• Recap:
• Total Man Hour = Total hours work a day per worker x Total number of
workers x Total numbers of days worked over the specific period of time
• For a Month: Total hours work a Month per worker x Total number of
workers
• N/B:
• Average daily working hour = 8 hours
• Average days in a week = 5 Days (minus weekends and public holidays).
• Average weeks in a month = 4 Weeks
• Total hours work a Month per worker = 8 x 5 x 4
• Total hours work a week per worker = 160
• == Assuming 8 workers worked
• Man Hour the month = 160 x 8
• Total manhour for the month = 1280 Man Hour.

5. LET’S CALCULATE MAN-HOUR FOR TISCO OFFICE FOR THE
MONTH OF MARCH

6. • Hours worked per day x number of staff x total number of days
worked in the month = Manhour
8hrs x 9 staff x 20 days = 1,440 Manhour
Excluding public holiday
There are situations where an employee work
for more than 8 hours a day, in this case the
number of hours work will be used instead of
the average daily working hours.

7. LET’S CALCULATE MAN-HOUR FOR GNL FOR THE MONTH
OF MARCH

8. • In GNL, we have day staff and duty officers
Man hour for day staff
11 staff x 8hrs x 20 days = 1,760 Man hour
Man hour for duty officers
19 staff x 24hrs x 14 in a month
19 staff x 12hrs x 31 days = 7,068 Man hour
1,760+7068 = 8,828 Man hour in month of March by GNL

9. 976-656 = 320 Man-hour
8hrs x 2 x 20 = 320 man-hour

10. Significance of Manhour
One significance of manhour is that by dividing the total
number of man-hours by the total number of workers
available, the man-hour concept has the advantage of
allowing one to calculate the impact of staff changes on the
total amount of time needed for a task. A team of two
workers will finish a task that requires twenty man-hours in
ten hours, whereas a team of five workers will finish it in four
hours.