Before we look at this question closely, we should first make an important distinction. The number of hours you teach in the classroom (often called contact hours) are not the same as the number of hours you will be expected to be in school, often confusingly called contract hours.
Next, it is important to appreciate that different teaching jobs have different typical hours. There are basically three types of jobs available.
Government and Private Schools
Most schools abroad work normal office hours so you will probably need to be in school, Monday to Friday, from 7:30 a.m. (in many Asian countries) until 4:00 p.m. This equates to around 40 hours per week. You will not have to teach for all of those hours but a typical teaching load would be around 20-25 hours per week. When you are not teaching you will be expected to prepare your lessons, mark homework and do any other administrative tasks required by the school.
In this setting you have the benefit of weekends off, although should you wish to do additional lessons privately this would also be possible.
Salaries for government schools are usually above the average monthly earnings of the general population of the area you are in.
As the name implies, this type of teaching will be for corporations or businesses. As such there will be two different types of teaching situations. Some companies offer their staff time within their working days to learn English while others don’t.
If you are teaching outside of their working day this means teaching will cover the following possible time frames.
1) Very early before they start their regular work
3) Evenings after they finish their regular work.
This means if you are working for a number of companies with different time frames you can end up with a very long working day. It can also mean that you don’t start work until the evening.
It is obviously very important to limit yourself to what is possible in this teaching situation.
Private Language Schools
The main point here is that private schools do most of their business (teaching) outside of normal working hours. This means the majority of your teaching will take place both in the evening and during weekends.
If you do work on the weekend you may only have to teach on odd or even weekdays. Monday is day one, so odd weekdays are Monday, Wednesday and Friday, while Tuesday and Thursday are even.
Typical teaching hours would be around 25 hours per week but again you will be expected to plan and create materials for your classes, which could typically add an additional 10 hours a week to your schedule.
Some Cultural Aspects
There are obviously some cultural differences in terms of a “normal working week” throughout the world.
Muslim countries variably recognize the weekend as Thursday and Friday, Friday and Saturday or even Saturday and Sunday depending on the country.
Some European and Latin American countries have a midday break (siesta) which can last up to 2 hours, particularly in rural areas. Midday breaks are not uncommon throughout China also.
The main point is that you should make yourself aware of the customs and practices of any country that you plan to teach in.