Open Tax Solver 22.07 OpenTaxSolver (OTS) is a free safe & secure application for calculating your USA Federal 1040 and State income taxes. It has a graphical interface for easy entry of your information. OTS assists you in doing the otherwise tedious tax calculations, while showing the intermediate and final numbers. It can automatically fill-out your numbers onto the official government tax forms. Now covers State Taxes for a dozen of the larger states which impose income taxes: OH, NC, NJ, NY, VA, PA, MA, AZ, CA,