According to the same survey, the average cost of a complete bathroom renovation in 2013 was about $15,000. By some estimates, a complete renovation in 2015 will be around $15,500 to $16,000 on average. Since one bathroom renovation can cost under $10,000 and another over $50,000, the average can be deceptive.The best way to budget for your new bathroom is to make an estimate based on the size of your bathroom and the inclusions you want.he size of your bathroom is going to be a factor in the cost of your renovation, but since so much of a bathroom is tiled, tiling costs will also be a significant cost.