A Ph.D. (mechanical) at IT Guwahati typically takes around 5-6 years to complete. There is no fixed time limit to complete a PhD at IIT Guwahati as there are several factors that affect your PhD degree. My friend submitted his thesis last December and it’s still under review. It has almost been 7 years and he is expecting his PhD in the near future. Many of his batchmates are still working on the thesis and very few have submitted it. Many seniors completed their Ph.D. exceptionally early within 2-3 years. 

Talking about Mechanicals specifically, the average time taken to get a Ph.D. is about 5–6 years no irrespective of your previous degree. However, the situation might be different if you have done MTech from the same institute.

On average, it takes 5–6 years of intense hard work to get a Ph.D. from IIT Guwahati.