Debt consolidation entails taking out one loan to pay off many others. This is often done to secure a lower interest rate, secure a fixed interest rate or for the convenience of servicing only one loan.

Debt consolidation can simply be from a number of unsecured loans into another unsecured loan, but more often it involves a secured loan against an asset that serves as collateral, most commonly a house. In this case, a mortgage is secured against the house. The collateralization of the loan allows a lower interest rate than without it, because by collateralizing, the asset owner agrees to allow the forced sale (foreclosure) of the asset to pay back the loan. The risk to the lender is reduced so the interest rate offered is lower.

Sometimes, debt consolidation companies can discount the amount of the loan. When the debtor is in danger of bankruptcy, the debt consolidator will buy the loan at a discount. A prudent debtor can shop around for consolidators who will pass along some of the savings. Consolidation can affect the ability of the debtor to discharge debts in bankruptcy, so the decision to consolidate must be weighed carefully.

Debt consolidation is often advisable in theory when someone is paying credit card debt. Credit cards can carry a much larger interest rate than even an unsecured loan from a bank. Debtors with property such as a home or car may get a lower rate through a secured loanusing their property as collateral. Then the total interest and the total cash flow paid towards the debt is lower allowing the debt to be paid off sooner, incurring less interest. In practice, many people are in credit card debt because they spend more than their income. If that habit continues, the consolidation will not benefit them much because they will simply increase their credit card balances again.