Because you're borrowing less money as you repay the principal. Like, if you take a loan at 6% with monthly payments, that means each month you owe 0.5% of the

Because you're borrowing less money as you repay the principal. Like, if you take a loan at 6% with monthly payments, that means each month you owe 0.5% of the current outstanding principal in interest. (6% / 12 months) Probably your question should be closer to "why is it so normal for loan terms to be stretched so long"