Quite high I reckon.
Here's his Marvel stats.
It scales with belief and Christmas spirit, so it's impossible to nail down. Plus some of his abilities bend space/time and shape reality. He can straight up do magic. He may also be a dire Shoggoth. Anywhere from average 50yo human to Supe's base level are typical, but it depends on who he's meeting on his adventures and what country he's in.
>green bar indicates strength during Christmas Eve
>doesn't have any gifts or pieces of coals for anyone else in the room