Get an INSTANT estimate of the cost to Refinish Bathtub! Our free calculator uses recent, trusted data to estimate costs for your Refinishing Bathtubs project. For a basic 1 refinishing project in zip code 47474, the benchmark cost to Refinish Bathtub ranges between $412.59 - $959.35 per refinishing.To estimate costs for your project: 1.Set Project Zip Code Enter the Zip Code for the location where labor is hired and materials purchased.ur free calculator uses recent, trusted data to estimate costs for your Refinishing Bathtubs project. For a basic 1 refinishing project in zip code 47474, the benchmark cost to Refinish Bathtub ranges between $412.59 - $959.35 per refinishing. To estimate costs for your project: 1.