Mortgage & Debt Calculator | True Monthly Cost | StandUP Advisors
Tool · Mortgage & Debt

The real monthly cost of a house. Not the principal-and-interest version.

Most mortgage calculators give you principal and interest and call it done. That's roughly 70% of the actual monthly nut — and the missing 30% (property tax, insurance, HOA, PMI) is where the unpleasant surprises live. This one shows you all of it, plus what an extra principal payment actually saves.

Run your numbers
Free calculator below — toggle between mortgage and any fixed-rate loan.
Open the Calculator ↓
What the calculator does

In Mortgage mode, drop in home price, down payment, rate, and term. Toggle on the add-ons that apply — property tax, insurance, HOA, PMI (auto-on if down payment is below 20%), and any extra principal you'd like to throw at it. The breakdown bar shows where each dollar of your monthly payment actually goes. The extra-principal toggle shows how much you'd save in interest and how much faster you'd pay off the loan.

In Loan / Debt mode, the calculator collapses to a clean fixed-rate loan calc — auto, student, personal, business. Same amortization math, no homeownership add-ons.

The Calculator

Mortgage or loan. The full math, including the parts the listing skipped.

Optional Add-Ons
Property Tax (annual)
Home Insurance
HOA Fees
PMI (auto if <20% down)
Extra Principal (accelerates payoff)

Total Monthly Payment
principal, interest, taxes, insurance, HOA, PMI
Principal & Interest
just the loan
Total Interest Paid
Monthly Payment Breakdownwhere each dollar goes

Illustration only. Excludes closing costs, escrow shortages, points, and rate changes. PMI shown when down payment is below 20%. Actual figures vary by lender and locality. Not a lending offer.

What to look for in the numbers

The decisions that actually move the needle.

Total monthly payment, not principal and interest. The "I can afford the mortgage" math people do in their heads usually ignores property tax (often 1–1.5% of home value annually), insurance, HOA if applicable, and PMI if down payment is under 20%. Combined, that's often 25–40% on top of the P&I figure. Always know your actual monthly nut before you sign.

Extra principal is the cheapest "investment" most homeowners overlook. Toggle the Extra Principal switch above — you'll see the math on your loan in real time. Here's the asymmetry worth knowing before you do: an extra $200/month shaves nearly 8 years off a $250K mortgage at 6.5%, but only ~3 years off a $1M one. Same $200. Smaller loans get faster payoff; bigger loans get bigger dollar savings. The return is your mortgage rate — guaranteed, no market risk. Compounding works in reverse on debt.

Term length is the lever most people don't consider. A 15-year mortgage at the same rate costs about 50% more per month but cuts total interest paid by roughly two-thirds. If cash flow allows, the math is decisive — but cash flow is the constraint that usually decides it.

PMI is real money. If down payment is under 20%, lenders typically add 0.3–1.5% of loan value as PMI annually. On a $500K loan that's $1,500–$7,500 per year — until you've built 20% equity. Always factor this in when comparing "10% down vs. 20% down" math.

The monthly number is one piece. The "should I buy" question is the harder one.

For that, check out the Rent vs. Buy calculator — or book a call to talk through the decision in your specific situation.