Is using treadmills better the running or jogging outside?

If you were to work equally hard for equally long, you would burn the same amount outside as on a treadmill.

Running outside have two advantages:

-it's less boring

- it usually offers more natural variation which tend to make outside a better workout.

OTOH outside can be too hot/cold/rainy/sunny/scarytraffic/dark etc etc, in which case a treadmill workout is better than no workout.