Is it better to start with cardio or weights at the gym?

Are you asking about one day at the gym? You should always warm up a bit before doing any intense exercise.  That doesn't mean you need to do a full cardio workout before doing your weights. It also depends on how much time you have and how many times you go to the gym or workout at home. Are you doing both each time you work out?  

Over time, building muscle will increase your ability to burn fat. Cardio is important not only for burning calories but also improving your overall endurance and fitness.

Opinions differ, but much of what I've read suggests weights first, to get max benefit. Cardio first tends to tire a person so they have less energy to lift well. You could always do it both ways and see what works best for you. 

Weights FIRST! If you're looking to lose weight, build up some muscle first to increase base metabolism rate and when you start cardio, you're going to burn so much calorie so quickly you'll be like a living furnace!!

Cardio at home, weights at the gym.