Paying extra on your mortgage is a good idea.

It can shave years off your loan and save tens of thousands of dollars in interest charges.

Paying fees to pay extra on your mortgage isn't.

Despite all the ads, you don't need an accelerated payment plan from a mortgage service company that costs hundreds of dollars a year.

There are three free and easy ways to pay your mortgage off faster by making the equivalent of 13 mortgage payments a year instead of the standard 12.

Increase your monthly checks by one-twelfth. Your lender will automatically deduct the additional money from your balance.

Make one extra payment a year. This works especially well if you get an annual bonus, or always receive a sizable income tax refund. Just add the money to your next monthly payment.

Pay half your regular monthly mortgage payment every two weeks. Although a few mortgage companies allow customers to switch to bi-weekly payments at no charge, most won't do that, nor will they accept partial payments. But you can ask your bank or credit union to have the money automatically transferred from your checking account to a special savings account every two weeks and then transferred to your lender at the end of every month.

How much could you save?

A typical $200,000 loan at 6.25% would take 30 years to repay and cost $243,300 in interest with the traditional 12 payments a year. Make the equivalent of 13 monthly payments and the loan would be retired in 24 years and you'd only pay about $188,000 in interest -- a savings of $55,555.

Of course you don't have to keep your loan for decades to benefit from extra payments.

You'll immediately begin adding to your equity (the difference between what your home is worth and how much you owe on your mortgages.) That will allow you to ditch private mortgage insurance sooner, take out a larger home equity loan in an emergency, and pocket a larger profit if you sell.

Our mortgage payment calculator will show how much you could save on your loan. Be sure to click on "Show Amortization Schedule" to see how much you'd pay in total interest.

When you buy an accelerated, bi-weekly payment plan from a mortgage service company, you're essentially asking it to make you pay your mortgage off early.

Indeed, that's the service companies' big selling point -- that you don't have the discipline to do it on your own. You need them to collect your bi-weekly checks and fine you if you miss one of your voluntary payments.

They say the threat of those penalties, and the hundreds of dollars they charge in set-up and maintenance fees, are worth it to save tens of thousands of dollars in the long run.

But it's not.

Start-up fees range from $200 to $500. Many also charge processing fees of anywhere from $2.50 to $10, and monthly or annual maintenance fees. While some service companies pay interest on the money they're holding, that won't come close to covering all the fees.

If you paid a $250 initial fee and then $10 a month processing fee you'd spend $370 in the first year and $2,650 over 20 years. If you didn't make all 26 payments a year on time and incurred any late fees, you'd pay more.

So when you get a mailer or phone call inviting you to pay a company to make money on your mortgage payment, thank them politely and tell them you don't need their help.

By Stef Donev

Interest.com Contributing Editor

Have a question about your finances? Ask us at editors@interest.com