How to Calculate Working Hours - Calculate Man hours How to Calculate Working Hours. In this publication we look at the concept of calculating working time and how average annual working time differs from one country to another.

Working hours – Man-hours, meaning

The hour of work is the time paid work. Unpaid work, such as personal household duties or caring for children or pets, is not considered part of the work week. 

Many countries regulate the working week by law, including minimum daily rest periods, annual holidays and the maximum number of working hours per week. 

Working hours may vary from person to person, often depending on economic conditions, location, culture, lifestyle and the profitability of the individual’s livelihood. 

Normal working hours refer to legislation to limit working hours by day, week, month or year. 

The employer pays higher rates for overtime hours as required by the law. 

The standard working time in the countries of the world is about 40 to 44 hours per week (but not everywhere: from 35 hours per week in France to up to 105 hours per week in North Korean labor camps) and overtime payments are approximately 25 to 50 percent higher than regular hourly payments.

How to Calculate Working Hours – Maximum number of working hours

The employee cannot exceed the number indicated on the Legislation relating to maximum hours of work.

How many hours of work do you have per year?

If you divide 365 days into seven, it’s 52,143 weeks a year.

In leap year we divide 366 days by 7, we have 5,286 weeks per year.

If we take Saturday and Sunday off every week, we have five days per week.

52.143 x 5 = 260.72 days.

52.286 x 5 = 261.43 leap year days.

In fact, there are 260.72 to 261.43 workdays a year.

If we take it that they work 8 hours a day, we have.

260.72 x 8, corresponding to 2085.76 hours per year.

261.43 x 8 resulting in 2091.44 hours per leap year.

Definition of Average annual working time

The average yearly number of hours worked is defined as the total number of hours actually worked per year divided by the average number of persons in employment per year. 

The following chart shows the average annual hours worked by country.


How to Calculate Working Hours - Calculate man hours
The graphics and the data are extracted from the OECD (OECD (2022), Hours worked (indicator). doi: 10.1787/47be1c78-en (Accessed on 18 June 2022)

The data are published with the following caution:

The data are intended for comparisons of trends over time they are unsuitable for comparisons of the level of average annual hours of work for a given year due to different sources and calculation methods.

Real hours worked include:

The normal hours of work of full-time, and part-time employees. 

Paid or unpaid overtime. 

Hours worked in extra employment.


Hours not worked due to statutory holidays.

Vacation leave with pay.

Illness, injury and temporary disability.

Maternity leave, parental leave, education and training. 

Slack work for technical or economic reasons, strike or labor dispute, bad weather, compensation leave and other reasons. 

The data cover employees and self-employed workers. 

It is measured by the number of hours per worker per year. 

In the next post, we will review some very useful information about the types of valves used in piping.

How to Calculate Working Hours – Calculate Man hours.