Comparing Investments This calculator compares the net gain of a taxable investment versus a tax-favored one. You are viewing this website at a small screen resolution which doesn't support calculators. Click here to view this calculator. Related Content Eight Mistakes That Can Upend Your Retirement There are common mistakes you can avoid when saving for retirement. Tax Deductions You Won't Believe Here are some examples of deductions from the IRS that were permitted and some that were, uh, too creative. Put It in a Letter A letter of instruction provides additional and more personal information regarding your estate.