1) Standard
(PES A/B1, 9th Week Onwards of PTP)
How you know you will be in a Standard Batch: you are physically okay, and have earned at least a silver in NAPFA.
You will have a shorter BMT, and are in the best position to aim for Command Schools. However, as you will have to cover the same amount of content in less than half the time of an Obese batch, you will be rushing everywhere. Expect admin time to be no more than an hour a night at very most. In addition, some recruits might find their fitness actually decreasing, since the emphasis is on quickly learning army skills instead of physical training.
2) PTP
(PES A/B1, 1st to 8th Week of PTP)
How you know you will be in a PTP Batch: you are physically okay, but have not earned at least a silver in NAPFA.
PTP stands for Physical Training Phase, and as the name suggests, this is a separate and distinct part of your BMT experience for building up your physical fitness to prepare for the actual BMT.
3) Obese
(PES BP)
How you know you will be in an Obese Batch: you are physically okay, except for a BMI exceeding 27.0.
Obese BMT aims to slim you down gradually and healthily over 19 weeks. There is no separate and distinct period for physical training - instead, weight loss activities are spread throughout your time there. This brings along the benefit of having a relatively relaxing BMT experience, where admin time can be several hours long. Also, you get to do dancing exercise with music, which makes everyone else jealous (personal experience).