loan amortization

[Jordan Lagrassa]

I recently built a house and with the loan it was for 300K for 30 years . I have heard of you make one extra payment per year to principal it would cut down your loan to about 18 years. My question is does anyone know of a tool I can use to figure out how much I would have to pay every year towards principle to cut the loan down to 7 years . If there is no tool I'm open to any ideas anyone has to help me figure this out. Thanks 

[Wayne Brooks]

Yes, you can google up "amortization calculator".  The simple thing to do would be calculate your loan at a 7 year amortization.  That would be the Exact monthly payment to pay it off in 7 years.  Note, the earlier in the life of the loan you pay extra,,the more overall you'll save, but realize everything extra you pay, you are earning Exactly whatever interest rate your loan is, on your extra money.