Find an overview and estimated costs for bariatric weight loss surgery. Federal government summary of different types of weight-loss surgery estimates average cost is $15,000 to $25,000 (2016); with medical inflation to 2022, the range would be about $18,000 to more than $29,000. Find costs under Definition & Facts. By the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) of NIH.