Interest rates constantly fluctuate, so when is the time right to refinance your home? One of the tools that can help you decide this is a mortgage calculator.

It shows you what your new payments will be, and whether the difference is worth the leap right now.

The most common reason to do a straight refinance is to take advantage of lower interest rates to lower the payment or reduce the term (the number of years to finish paying off the note.)

To work with a refinance mortgage calculator, you will need to know details about your current loan like the original loan amount, the original term (number of years to pay off), the number of months you have already paid, your interest rate, and, perhaps, the number of years until you intend to sell.

For the new loan, the mortgage calculator will want to know the loan points and interest rate on the new loan and approximate closing costs. Do not even try to figure it out on your own. Just look up several refinance mortgage calculators on the net and open them in separate windows or tabs in your browser. Start filling the figures into one after another, setting them to calculate as soon as they are loaded. Now, take a break, and relax. When you are ready, return to the computer for the news.

Have a look at the figures for monthly payment, term, and the breakeven date. See if the mortgage calculators come anywhere near agreeing. Like the scoring in the old Olympics, throw out the high and low numbers and average the rest to get an approximation on your savings.

What you are concerned with is the breakeven date. The breakeven date is determined by the mortgage calculator as the month in which the savings on the mortgage covers the cost of the refinance itself. If the breakeven date is five years down the road and you are selling in four, then it does not matter how good the interest rates are.

You will still lose money. On the other hand, if you are expecting to stick around more than five years, now is the time to go for it. You can redo the figures on the mortgage calculators with different interest rates and different terms (number of years to repay) to see where the breakeven point and the terms line up with what you can afford to give you the best deal.

But what if you have a different reason to refinance, say to "cash out" the equity of your home, for whatever reason. Emergencies happen, debt consolidation need to occur, and a good mortgage calculator can still help you figure out how to get your best deal.

When you feel like you know what you want, print out the best options, collect up your documents and head to the mortgage broker. One note: a refinance is a new note; you will be paying all appraisal fees, points and closing costs associated with a brand new note. The mortgage calculator does not take this into account. Proceed carefully and cautiously.