Let us face the fact that salary scales in the vast majority of Thai schools are not good to say the least, however what is so annoying is, that even if you make an effort, do a professional job, kids, other teachers and parents like you, turn up on time, don't go sick (even if you are) and don't make a fuss about the crap you have to put up with, you are treated just the same a some joker who doesn't give a hoot and flip flops around for a couple of months and leaves you doing their classes because they've buggered off to Bali.
Bearing that in mind, the math bears out the low income status of a teacher, other than being at a bonafide international (professionally affliated, registered etc. etc.) school, of course.
The medium salary seems to be 35,000 Baht per month or 315,000 Baht for a nine months, yep, you might say but, oh my school pays for holidays but as many have said in multiple threads, many do not or simply get you in some other way via visa payments, summer camps, weekends etc. etc. blah blah blah...

Still 35,000 per month is good you say, especially for only 100 hours of work (25 x 4 weeks), yeah right. In fact your working a full week and probably hitting the 40 hour mark but never mind it is teaching, but not as we know it.
So what does our 100 hours a month get us around 350 Baht an hour minus your tax, travel expenses, accommodation, visa, aggravation of the worst kind, harrassment and the list goes on. SOooo... as you trudge off home after another fun packed day you can be sure that as your pot of gold sinks the owner of the school is laughing all the way to the bank.
Oh, that's right... you didn't see them as they left school three hours before you in that nice new BMW, Mercedes etc. etc. Wouldn't want to lose face as they pulled into the bank car park.

So what's your job worth... As they say in LOL 'UP TO YOU'
