Q: Dear Dr. Don,

I have a 20-year mortgage on my house and make roughly an extra payment a year. How many years am I really knocking of my mortgage? My loan was for $220,000 at 5.625%.

-- John Juncture

Dear John,

If you're a regular reader of this column, you know I'm not a big fan of biweekly mortgages. I don't see the need when you can do it yourself and save by making additional principal payments on your existing mortgage.

Making the equivalent of an additional mortgage payment each year gets you roughly to the same point as you'd be with a biweekly mortgage. You can figure it out for yourself by using the amortization feature on Bankrate's mortgage payment calculator.

I used the calculator for your mortgage and, if you've been faithful about making that additional payment every year since the start of the mortgage, your 20-year mortgage will be paid off in 17 years and five months.

That will save you about $21,800 in interest expenses, although that number ignores the tax impact of any lost mortgage interest deduction. (Bankrate's calculator rounds the interest rate up to 5.63%, so the savings and the interest expense aren't exact.)

I assumed that you made additional principal payments each month equaling about 1/12 of a scheduled monthly payment. The calculator gives you other options for additional principal payments.

Bankrate also has a biweekly mortgage payment calculator. I ran your inputs and it showed you saving $22,239 in interest and having the loan paid off in 17.3 years (17 years and four months).

Who needs a biweekly mortgage when you can do it yourself and not make the additional payments contractual?

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