Mortgage costs, worked out
Every number on this site shows its working
Most mortgage advice rounds to a range and moves on. We run the arithmetic, state the assumptions, and say when the answer is that a thing isn’t worth doing — which, for the mortgage interest deduction, is most of the time.
Start here
The questions that bring most people to a site like this.
- What is my mortgage interest deduction worth?Usually less than you think, and often nothing at all. The calculator starts with whether itemizing beats the standard deduction.
- When can I stop paying PMI?Your date under the Homeowners Protection Act, what the premiums cost meanwhile, and how much sooner extra principal gets you there.
- How much cash do I need at closing?Split into money that's genuinely spent and money that's only paid early — a distinction most calculators skip.
- Why did my fixed-rate payment go up?Almost always escrow, not interest. How the account works and how to check your servicer's annual analysis.
Keeping a cheap rate
Twenty percent of American mortgages carry a rate below 3%. Three ways that gets discussed, only one of which exists.
- Assumable mortgagesReal today on FHA, VA and USDA loans. The equity gap kills most of them, and two traps land on the seller.
- Portable mortgagesStandard in the UK and Canada. The reason it doesn't exist here is the bond market, not politics.
- The 50-year mortgageIt would cut $267 off a $400,000 payment and add $456,000 in interest. Shelved by the FHFA in January 2026.
Fifty states, three different answers
The federal deduction works the same everywhere. Whether your state lets you claim it too, and at what rate, is the part that varies — and it runs to thousands a year on identical loans.
33
allow itemizing
8
tax income, no itemizing
9
no income tax