For all the other taxcasting nerds on here....
I've been playing around with 2 products for running tax simulations. Both seem to be FREE as long as you are just using them to run scenarios. Both of these apps are intended for tax professionals doing tax returns for customers. They don't have tons of wizards to walk you through reporting so you have to be a little familiar with your tax situation to make sure you get everything entered that applies to you. But after the initial entry is done.... this makes it super quick to go back and plug in different numbers to simulate different scenarios.
Tip: If you plan to review drastically different scenarios, you can create different "customers" to represent different stages of your life. For example I have one customer that basically represents our current situation... current age, 3 kids in the house, etc. Then another "customer" that represents "our future household" after the kids are moved out, when we are older. It's easier to jump between "customers" than to go back and delete (and then re-add) your dependents since it requires valid SSNs etc. The trick is to adjust your(and spouses) date of birth for future versions of your household since some variables are age-dependent.
Another tip: Just to avoid an Equifax-like data breach .... since I don't actually file out of these systems, I don't put in our real address, SSNs, etc.
1) Lacerte Individual Tax (which seems to be owned by Intuit now).
Is a desktop app. Pretty clunky and not super-intuitive, but it does the trick. This is an EVAL version... but it seems to tally an evaluation towards your total if you run an "analysis", which is a more advanced function. It seems to calculate all the totals correctly without the need to run that analysis.
2) Intiut ProConnect Tax Online.
This one is online. It's easier to use than Lacerte. This is not an eval version, but the full software that appears to let you create as many real/fake customers and scenarios as you like. It only charges you if you actually try to file. While not wizard-based to make sure you don't forget anything, it does have a "check return" feature that gives you a list of things to make sure you don't leave out.
I haven't found every nook and cranny, but both seem to support partnership returns, estates, S-Corps, etc.
Both systems generate not only a summary, but all the actual IRS forms themselves. The print functions are disabled. You can't print the forms, but every form and all the supporting worksheets, etc are there.
Note: These systems can't replace the advice of a good CPA... but if you are like me you don't want to waste (or pay for) your CPA's time with questions like... In 15 years, if 2 of my kids are out of the house AND we are doing $35K in Roth Conversions AND my wife makes $8000 that year but puts it all in a Solo 401(k) AND we sell (for $70K) the rental on Jones St. that we bought 2 years ago AND we live it FL then.... you get the picture. This way you can at least do the leg work and just run it by your CPA before you make a certain scenario part of your FIRE plan.
Anyone have other suggestions for software to do planning like this? Any CPAs out there care to share cheap/free solutions for nerds who want to run the numbers themselves?