Got some questions about your finances, such as which loan to take out, investment to choose or simply where your fiscal efforts stand in comparison with others?

Well, Millionaire Mommy Next Door has compiled a list of 110 personal finance calculators that are free and designed to help you find fast answers to your financial questions. And a few of them take tax taxes into account. For example:

• Estimating the tax-equivalent yield for a municipal bond
• Comparing returns on taxable vs. tax-advantaged investments 
• Computing your potential estate tax liability
• Checking on your portion of the country's overall tax burden

Another blogger, however, says some you shouldn't bother with some of the mathematical comparisons, or do so only with extreme caution.

Penelope Trunk, aka the Brazen Careerist, has these contrarian words about some common types of calculators.

Salary comparison tool: The reason salary comparison tools exist is so people can make sure they're getting paid enough. If you need to use such a tool, however, your career is in trouble.

Cost of living calculator: The problem with this kind of tool is that it gives you information you can't use. You need to know which city will make you happy, not which city will save you $20,000 in housing costs.

Renting vs. buying calculator: It used to be that the American dream was about buying a house. Today, the new version of the American dream is about time and personal development -- and the best way to get more time is to not be tied down to a house.

Retirement calculator: Is there anyone out there who still thinks retirement exists? Moreover, who would want to sit around doing nothing all day?

You can read all of Penelope's arguments against putting too much stock in generalized calculators here.

Just one tool: Now I'm not saying you shouldn't try out some of the 101 financial calculators that Millionaire Mommy found, and kudos to her for all her work in tracking them down.

Personally, I do find many of the online calculators to be very useful ... as well as scary and often entertaining.

But I do want to toss in my two cents about such comparative or predictive findings. In making any financial decision, the computations they provide are just one tool. So use them, but don't rely totally on their results.