What a calculator can tell you — and what it can't
Every mortgage calculator on the internet does the same arithmetic. Where they differ is in what they quietly assume, and those assumptions are where Michigan buyers get surprised. A national calculator doesn't know that our property taxes bill in summer and winter cycles, that a Principal Residence Exemption changes the school operating portion once the home is your primary residence, or that two houses with the same mailing address can sit in different taxing jurisdictions with different millage.
So use these to get oriented. They'll tell you whether you're in the right neighbourhood, what happens when you move one variable, and which questions are worth asking. What they can't do is account for how your income is documented, what a particular lender's guidelines say about your file, or what the appraisal comes back at. That's the part that decides your actual number, and it's a conversation rather than a form.
I'd rather you play with these first. Someone who's already run the math asks better questions, and I don't have to spend the first half of a call explaining what escrow is.
The eight calculators, and when each one earns its keep
Payment. The starting point. Principal, interest, taxes and insurance in one place. Most useful for testing how sensitive your comfort level is to a change in price — move the number and watch what happens.
Affordability. Works backwards from your income and existing obligations toward a price range. Treat the output as a ceiling, not a target. Lenders look at what you can carry; you should decide what you want to carry, and those are rarely the same number.
Refinance. Compares keeping your current loan against replacing it, including lifetime interest rather than just the monthly line. The lifetime column is the one people skip and later wish they hadn't.
Rent vs buy. Genuinely useful in this market, and the most commonly misused. It's sensitive to how long you'll stay — the answer flips depending on that one input, so be honest about it.
VA. Structured around the VA benefit, including the funding fee and the exemptions that apply to some veterans. If you served, start here rather than with the standard payment calculator — the math is genuinely different.
DSCR. For investment property, qualified on what the property earns rather than what your tax returns show. If you've been told your returns don't support another mortgage, this is the one to run.
Fix & flip. Purchase, rehab budget and after-repair value against the deal breakdown. Built for people who already know what they're doing and want to sanity-check a specific property.
Cash to close. The one people should run first and usually run last. It answers the question that actually stops purchases — not what the monthly is, but what you have to bring on signing day. That one has its own page, because Michigan's tax structure makes it the calculation everybody else gets wrong.
Three Michigan quirks the national tools miss
Summer and winter taxes. Michigan bills property taxes twice a year on cycles that don't line up neatly with a closing date. Which bills have been paid, which are coming, and how they get prorated between buyer and seller moves real money at the closing table — and it moves it in either direction depending on the month you close.
The Principal Residence Exemption. A home that's your primary residence is exempt from a portion of the school operating millage. Buyers are frequently quoted from the seller's non-homestead tax bill and conclude the payment is worse than it will be. It's one of the most common reasons someone talks themselves out of a house they could afford.
Jurisdiction, not town. A single mailing address can sit inside a city or out in a township, and occasionally in a different county altogether. City services come with city millage. That line item isn't a rounding error, and no calculator knows which side of the line your address falls on.
Other tools on this site
Not everything lives on this page. The cash-to-close estimator is calibrated against real Michigan closing disclosures rather than national averages. The seller net sheet works the other direction — what a seller actually walks away with after commission, transfer tax, title and proration. The down payment multiplier shows what a larger down payment does and doesn't buy you. And the closing costs guide walks the whole settlement statement line by line.
All of them are free, none of them ask for your email, and none of them pull your credit.