You want more than 1.5m but probably not more than 2m. Hip measure is more important than waist. That is the widest area and determines how the pattern will be laid onto the cloth. If you get pleats you need more cloth than for plain front as you need more width for the top of the front panel and need to move the pattern to accommodate this. Cuffs will require a bit more length than plain bottom. Some cloths require you lay the pattern pieces in one direction and not reverse the direction of the two pieces. Could be due to a pattern in the cloth or the weave. If it is a one way cloth and you reverse the pattern pieces you will see uneven coloration of the cloth. This may require extra cloth to cut in one direction. Some tailors are insistent about this and some are careless regarding this. You are better off getting extra cloth than not enough cloth and the cut becomes useless for you.