An ideal fat blasting workout would involve heavy weights, but here is a weight-free alternative. 

50 jumping jacks 

10 burpees 

30 squats 

50 crunches

10 calf raises (go slow!)

30 mountain climbers

5 push-ups

5 dips

1 minute of jump rope

20 lunges

10 burpees

30 squats

50 crunches 

50 jumping jacks

Complete circuit three times.