This is probably the best mortgage calculator in the world.
You can easily control your liabilities with it: Set a monthly prepayment and see the total interest and actual payment term shrink.
You have to choose between two mortgages and don’t know which one is best for you? There’s a tab for that.
You have a loan (mortgage, car loan, student loan, etc) and you want to get rid of it quickly? Go to the Freedom calculator page and enter your desired balance and time frame.
And … most importantly… stick with your plan. Small steps have great consequences in the long run.