Mortgage Calculators

Almost everyone starts in the middle. You find a house you like, put its price into a mortgage calculator, see a payment you could just about manage, and work outwards from there. It's backwards, and it's how people end up owning a house that technically fits their income and leaves nothing over.

The order that works runs the other way. Start from what you earn and owe, and let that set a ceiling. Then price a specific deal against that ceiling — the full payment, not the loan payment, because tax and insurance typically add a fifth to the bill. Only then look at houses. The affordability calculator and the mortgage calculator are the same arithmetic pointed in opposite directions: one works from income to a maximum price, the other from a price to a payment. Running both and finding they disagree is the useful outcome, not a mistake.

The one genuinely optional stage is the first. If you already know you're buying, the rent-versus-buy comparison won't change your mind — but if you're on the fence, it's the only tool here that can answer the question you're actually asking, and it's the one people skip.

A rate quote covers principal and interest. Almost nothing else about owning a home is in that number, which is why a mortgage statement so rarely matches what the lender first told you.

Property tax and homeowners insurance are usually collected with the payment and held in escrow, adding something like a fifth of the total on typical figures. Below 20% down there's PMI on top, until the balance reaches 78% of the purchase price. Closing costs are a separate lump due at signing, commonly a few percent of the loan and paid in cash rather than financed. And none of that touches maintenance, which no calculator on this page models because it doesn't follow a formula — it follows a roof.

The practical consequence: the gap between a rate quote and a real housing budget is wide enough to change which houses you should be looking at. That's the gap these tools exist to close, and it's why the affordability and closing-cost calculators matter as much as the payment one.

Most mortgage advice ends the day you get the keys, which leaves out the part that lasts thirty years. Five of the twelve tools here are for people who already own the place.

Three of them attack the same thing — the interest you'll pay — from different angles. Extra monthly principal shortens the term and costs nothing. Biweekly payments do the same via a squeezed-in thirteenth payment each year, though it's worth checking what it costs to arrange: some lenders offer it free, while third-party services often charge a setup or per-payment fee that eats into the saving. A recast uses a lump sum to re-amortize and lower the required payment — the only one of the three that reduces what you're obliged to pay each month rather than what you choose to pay.

The other two respond to things outside your control. Refinancing is worth checking whenever rates move meaningfully below yours — with the caveat that a fresh 30-year term can raise lifetime interest even at a lower rate. A HELOC turns equity you've built into borrowable cash, which is genuinely useful and genuinely a second lien on your home. Neither is a decision made once; both are worth re-running when the numbers change.