Should I roll my debt into my mortgage?
Sometimes. The monthly savings are usually real and usually large, and that's the part every other calculator shows you. This one shows you the second number too, because the decision doesn't make sense without it.
What does a lower payment actually cost?
A lower payment almost always means a longer term, and a longer term almost always means more total interest.
Take a car loan with four years left and roll it into a thirty-year mortgage. The monthly payment for that car drops dramatically, which feels like winning. You're also now paying for that car for thirty years, and the total interest can end up larger than the car was worth.
That's the trade. It's not automatically a bad one, because cash flow has real value when it's tight. But it should be a decision you make with both numbers in front of you, which is why this calculator shows total interest under each scenario rather than just the monthly difference.
What's the risk nobody mentions?
You're converting unsecured debt into debt secured by your house.
If you default on a credit card, it wrecks your credit and collectors call. If you default on your mortgage, you lose the house. Moving the balance from one to the other doesn't reduce what you owe, it changes what's at stake if things go wrong.
For a borrower with stable income and a plan, that risk is theoretical. For a borrower consolidating because they're already underwater on cash flow, it's not. Be honest with yourself about which one you are, because the calculator can't tell.
When does this actually make sense?
A few situations, consistently:
High-rate debt with a meaningful spread against your mortgage rate. Credit cards in the twenties against a mortgage in the sixes is a different conversation than a car loan at four percent.
A plan you'll actually follow for the freed-up cash flow, whether that's paying the mortgage down faster, building reserves, or a specific expense you were going to finance anyway.
And staying in the home long enough for the math to play out, since you're spreading the cost over a long term.
What goes wrong
One thing, over and over.
Someone consolidates their cards into the mortgage, the cards go to zero, and within two years the balances are back. Now they have the card debt again and a bigger mortgage, and the equity they used to fix it is gone.
If you're not confident the balances stay at zero, consolidating doesn't solve the problem. It buys you eighteen months and costs you your equity. That's the honest version and it's the one your lender should say out loud.
Run it before you commit
The monthly savings number is the easy part. What matters is whether the total cost and the tradeoff make sense for your situation, and whether there's a better structure than the obvious one.
Send me your numbers and I'll run it properly.