Yes, TurboTax provides a Capital Gains (or Loss) Tax Calculator.
You may need to use the calculator multiple times to run the different scenarios. For example, maybe you already know that one investment will have a short term gain while one has a long term gain. Or maybe one will have a long-term loss. Perhaps you have a carry over loss that will reduce your gains. So the calculator paired with a simple spreadsheet, will help you plan for those gains and losses.