Post 16

A-level means Advanced level and refers to the overall qualification.
The International A-level consists of two stages called AS and A2. AS stands for Advanced Subsidiary level. Students who complete the correct pattern of AS level units (usually 2 or 3 units at this level, depending on the subject) will be awarded an AS-level certificate or can continue the subject at A2.
A2 refers to the final stage of International A-levels. Students who have completed AS units in a subject move on to do A2 units, which are of a higher standard. Completing the correct sequence of units at both AS and A2 level means you have finished a full International A-level in a subject. University entrance is at the discretion of the university based on your AS and A2 grades.
In Year 12, students typically study four Advanced Subsidiary (AS Level) subjects. In Year 13, students typically take three of their AS Level subjects forward to a higher level, known as A2. Some students also broaden their studies by taking an additional AS Level subject in Year 13. AS and A2 unit examinations are held in May or June.
Compatible AS units may be combined (a process known as cashing in) to complete certifiable AS Level qualifications. Compatible AS plus A2 units may be cashed in to complete certifiable Advanced Level (A-Level) qualifications.
Statements of provisional examination results are released in August. Certificates of final qualification results are issued in October.

Edexcel, a Pearson company, is the UK’s largest awarding body offering academic and vocational qualifications and testing to schools, colleges, employers, and other places of learning in the UK and internationally. Edexcel was formed in 1996 by the merger of the Business & Technology Education Council (BTEC), the UK’s leading provider of vocational qualifications, and the University of London Examinations & Assessment Council (ULEAC), one of the major exam boards for GCSEs and A-levels.

Edexcel and CAIE are both examples of UK exam boards. They both provide a range of internationally recognized qualifications.

GCSE and IGCSE are qualifications that are at the same level. The IGCSE has been developed to be more relevant to students learning in an ‘international’ or non-UK context. The ‘I’ stands for international. These qualifications have become so popular that several independent schools in the UK are now moving away from the GCSE and adopting the IGCSE. However, in terms of entrance into post-secondary and other courses, the qualifications are seen as equivalent.
What is the difference between Edexcel and CAIE /IGCSE’s
There is no difference in the level or degree of difficulty between the IGCSEs offered by Edexcel and CAIE. The differences are only in the way questions are asked and the format of the exams.

The IGCSE is an internationally recognized qualification.

IGCSE exams are offered twice a year – in May/June and in January.

The results are generally released in August (for the May/June exam session) or March (for the January session).

The GCE A-level is a linear qualification taken over two years by students at school in the UK. International students can still take it but they should note they will take regional versions and will sit papers at slightly different times. The examinations take place in June.
The International A-level is especially for students studying outside of the UK. It follows a modular structure so you can build the qualification over time. Examinations take place in January and June.

This depends on the reasons for which you are taking A-levels. If you are taking them as a stepping stone to a UK university, then the number you take will depend on what the university requires or the number of UCAS points you need to get into your course. The most common combinations call for three full A-levels. For entry to universities in other countries, you will need to research their specific requirements. While A-levels are useful for some other reasons such as high school completion, employment, or career development, there are no requirements in terms of the number of subjects for these uses.

This depends on the caliber of the university you are targeting or the course you are hoping to get into. Some subjects are not seen as sufficiently ‘academic’ to be accepted by some universities. Many universities don’t give credit for marks achieved in General Studies, for example. Check with your chosen universities to see if they have a subject or two they won’t recognize.

There is no difference in the level or standard of the A-level offered by different exam boards. There are differences in emphasis and also some differences in the format of the papers. The Joint Committee on Qualifications (JCQ) ensures that all the boards offering A-levels offer them at the same standard.

International A-levels are offered in January, June, and October. However, not every module in every subject is offered in all sessions. Check with your exam officer for details.

Most universities in the USA will require an entrance exam such as SAT or ACT. It is up to each school to decide on your entrance requirements so make sure to ask each school that you apply to what you need to submit. It is unlikely that you can apply successfully with A-levels alone.

All degree courses require students to have not less than three A-levels or other equivalent qualifications. Some students opt to take additional AS-Levels, A-Levels, or other qualifications such as the EPQ. Additional qualifications can be one way of demonstrating the academic abilities that will be required for degree study. You can also demonstrate your abilities by exploring your subject beyond your exam syllabus. Universities may prefer a student who has read around their subject, and who shows a great passion for, and engagement with, their subject, over a student who may have taken more qualifications or more subjects, but who is unable to discuss their interests with any enthusiasm or in any depth.

If you cannot decide what subjects/courses to take, these are some key factors which you should take into account. 
Your interest in the subject
Where your strengths lie 
Your future career plans 
The ability to get a high Grade. Remember, you will be studying these subjects over the course of two years. It is essential that you do your research before selecting your A Level subjects to make sure you have made the right choice for yourself. Do not just follow subjects your friends/peers pick so as to stay in the same group, be adventurous and grab the chance to meet new people.