From an entry level English teaching position, CELTA, TEFL and TESOL certificates are more or less identical.
Earning any one shows that a potential teacher has undergone training specifically designed to teach learners English as a second or foreign language.
Having any one of these certificates allows for a school to see your qualifications while also meeting the minimum hiring requirements in many countries.
However, not all certificates are made equal. When employers look at your CELTA, TEFL or TESOL, they will consider how many credit hours were needed to pass the program.
Most schools require a minimum of 120 credit hours for a certificate to be considered worthy. More advanced certificates are closer to the 180 hour mark. As such, a TEFL can range from a level one to a level five TEFL. A TESOL is usually measured in academic hours and practical hours done to earn the certificate. While a CELTA is actually graded on three levels, a Pass, Pass B and a Pass A (With Pass A being an exceptionally good score). There are also opportunities to earn certificates like the TESL (Teaching English as a Second Language).
Keep in mind, some of these programs are just initial requirements in study. For example, if you want to follow ESL as a serious career, the CELTA program is the entry level to the various steps in the Cambridge-validated training programs. A person aiming for a Director of Studies Position would likely look at eventually earning the next level, a DELTA. However, if you’re just looking to get started in ESL, virtually any of these qualified and verified certificates will make you eligible for a teaching job abroad.
In short, the certificate doesn’t matter half as much as the number of hours and intensity of training the certificate supplies. Almost all of these programs with enough hours allows for work teaching English in a foreign country.
CELTA is generally accepted as the highest ranking of these certificates and the most prestigious, as it’s validated by Cambridge. It is important to remember that the CELTA program primarily focuses on adult learners, and many of the techniques learned here, while useful, must be altered if you are going into a career of teaching children or other young learners.
Overall, look at the options you have and the amount of time you have available to earn your certificate. Many can be earned online and the cost of these certificates varies wildly depending on the program. The more intensive programs will bequeath you a better skillset in the classroom, while online courses offer convenience and other resources.
Consider all of your options carefully and select the one most in line with the age group and level you plan on teaching, while keeping your personal resources in mind.