What 30 Years of a Mortgage Actually Costs (I Added It All Up)
By De Van Do -- January 20, 2026 -- 9 min read
Two Numbers, and Only One of Them Is Useful
Type a house price into any mortgage calculator and it gives you a monthly payment. That number is technically correct and practically misleading, because it answers a question nobody actually has. You do not want to know what the payment is. You want to know what the house costs.
Those are different questions by a factor of nearly three, and the gap is where most of the financial surprise of homeownership lives.
So I built the True Cost Calculator on this site to answer the second question, and then I ran a realistic purchase through it end to end. Below is every layer, what it contributes, and the multiple it all adds up to.
The House I Modeled
A $500,000 home with 20% down. That is $100,000 at closing and a $400,000 loan, 30 year fixed at 7%, which is the same loan used across the rest of this site so the figures reconcile.
For the surrounding costs I used property tax at 1.1% of value per year, homeowners insurance at $1,800 a year, and maintenance at 1% of value per year. No HOA.
Those three are assumptions, not computed facts, and they are the ones you should argue with. Property tax varies enormously by state and county, from well under 0.5% to well over 2%. Insurance has moved hard in coastal and wildfire exposed markets. The 1% maintenance rule is a long standing convention rather than a measurement, and for an older home it is optimistic.
I have held all three flat across thirty years. That is not realistic, and I want to be explicit about it, because it makes the final number conservative rather than alarmist. More on that below.
Layer One: The Loan
Principal and interest on $400,000 at 7% comes to about $2,661 a month.
Over 360 payments that totals roughly $958,036. Of that, $400,000 is the money you borrowed and about $558,036 is interest.
That interest figure deserves a moment. It is more than the price of the house. On a 30 year loan at 7% you pay for the house twice, once to the seller and once again to the lender, plus change. There is nothing pathological about that. It is what borrowing a large sum for three decades costs, and it is the reason the amortization article on this site exists.
Add the $100,000 down payment and you are at roughly $1,058,036 before a single other bill arrives.
How the Interest Is Distributed
The $558,036 interest figure is not spread evenly, and the shape matters more than the total for anyone who is not going to stay thirty years.
Splitting the loan into decades: in the first ten years you pay about $262,595 of interest and retire about $56,750 of principal. Eighty two percent of what you hand over in that decade is interest.
In the second decade it is about $205,296 of interest against $114,049 of principal, so sixty four percent interest.
In the third decade it finally inverts. About $90,145 of interest against $229,200 of principal, only twenty eight percent interest.
Nearly half the total interest on the loan is paid in the first ten years. If you sell or refinance in year seven, which a large share of borrowers do, you never reach the part of the loan where the arrangement starts working in your favor. You paid the expensive decade and left before the cheap one.
This is the single strongest argument for either staying put or taking a shorter term, and it is invisible in a monthly payment figure.
Layer Two: Everything Else
Now the costs that no mortgage calculator shows you.
Property tax at 1.1% of $500,000 is $5,500 a year, about $458 a month, and $165,000 across thirty years.
Homeowners insurance at $1,800 a year is $150 a month and $54,000 across thirty years.
Maintenance at 1% of value is $5,000 a year, about $417 a month, and $150,000 across thirty years. This one is lumpy rather than monthly. You do not spend $417 in a quiet month and then you spend $14,000 on a roof. Budgeting it monthly is how you have the $14,000 when the roof goes.
Those three together come to $1,025 a month and $369,000 over the term.
Stack them on the payment and your real monthly cost is about $3,686, not $2,661. The mortgage payment is only 72% of what the house costs you every month. Roughly one dollar in four goes somewhere a mortgage calculator never mentioned.
What Happens If You Let the Costs Rise
I promised to come back to the flat cost assumption, so here is what relaxing it does.
Escalating property tax, insurance, and maintenance at 3% a year, which is a modest assumption and below what insurance has actually done in several states recently, changes the surrounding costs from $369,000 to about $585,178 over the thirty years. That is $216,178 more than the flat model.
The monthly effect is more striking than the total. In year one those three costs run about $1,025 a month. In year thirty they run about $2,415 a month. They nearly double while your principal and interest payment stays frozen at $2,661.
That is the quiet reversal inside a fixed rate mortgage. People buy fixed rate loans for payment stability, and the loan does deliver it, but the loan is only part of the bill. By the end of the term the costs that do move have grown to nearly the size of the payment that does not.
With escalation, the grand total moves from about $1,427,036 to about $1,643,213, and the multiple moves from 2.85 times the purchase price to about 3.29 times.
The Multiple
Adding every layer: $958,036 in payments, $369,000 in taxes, insurance, and maintenance, and the $100,000 down payment.
The total is about $1,427,036 on a $500,000 house. That is 2.85 times the purchase price.
And that figure is the floor. I held taxes, insurance, and maintenance perfectly flat for three decades, which will not happen. Assessed values rise, insurance premiums have been climbing fast, and maintenance costs track inflation at minimum. I also left out closing costs on the purchase, utilities, and any HOA. Put realistic escalation into the surrounding costs and the multiple moves north of 3 without difficulty.
When you hear that a house costs about three times its sticker price over the full term, that is not a scare number. It is roughly what falls out of ordinary assumptions.
The Costs I Left Out
Three more things belong in a truly complete total, and I excluded them from the headline figure deliberately so that the number stays defensible rather than maximal.
Closing costs on the purchase. Typically 2% to 5% of the loan, so somewhere between $8,000 and $20,000 on this deal, paid on day one and never recovered.
Utilities. A larger home usually means a larger utility bill than the place you left, and while you would pay utilities as a renter too, the delta is real and rarely budgeted.
Opportunity cost on the down payment. This is the big one and the most contested. That $100,000 sitting in the house is $100,000 not invested. At a 6% annual return over thirty years it would have grown to roughly $574,349. That is not a cost in the sense that a tax bill is a cost, because the house may appreciate too and you have to live somewhere regardless, but leaving it out entirely makes homeownership look better than an honest accounting would.
I have kept all three out of the 2.85x figure. Add them and the number stops being a useful benchmark and starts being an argument. The point of the exercise is to give you a defensible floor, not to win a debate about renting.
The Single Biggest Lever on the Total
If the 2.85x multiple bothers you, there is one change that moves it more than everything else combined, and it is not the interest rate.
It is the term.
The same $400,000 on a 15 year note at 7% carries a payment of about $3,595 and costs about $247,156 in interest. Against $558,036 on the 30 year, that is $310,880 less interest for the same house at the same rate.
Fifteen year loans usually price below thirty year loans too. At 6.40%, a realistic spread, the payment is about $3,462 and the total interest falls to about $223,246. That is $334,790 saved against the 30 year at 7%, and it costs about $801 a month more.
Eight hundred dollars a month is not nothing, and for many buyers it is the difference between qualifying and not. But it is worth seeing the trade laid out honestly, because the usual framing has it backwards. The 30 year mortgage is not the normal option with the 15 year as an aggressive variant. The 30 year is a financing choice that roughly doubles the total interest in exchange for a lower monthly commitment.
Run both terms side by side in the calculator before you assume the 30 is the default. The multiple on the 15 year version of this house is closer to 2.2x than 2.85x.
What This Number Does Not Mean
I want to be careful here, because a figure like 2.85x is easy to misread as an argument against buying. It is not one, and pretending otherwise would be dishonest.
It is not a comparison to renting. The honest comparison is against thirty years of rent in a market where rent also rises, plus whatever you would have earned investing the down payment. This total says nothing about that on its own.
It ignores appreciation. If the home is worth more than $500,000 in thirty years, and historically that has usually been the case, a large part of this cost comes back at sale.
It ignores equity. Every principal dollar in that $958,036 is yours, not spent. At the end you own an asset outright and your housing cost collapses to taxes, insurance, and upkeep.
It ignores tax treatment, which may offset part of the interest and property tax depending on whether you itemize.
And it ignores the thing that made most people buy in the first place, which is that a payment on a fixed rate loan does not go up and a rent payment does.
The multiple is not a verdict. It is the real denominator you should be putting all of those other arguments over.
Run Your Own House Through It
My assumptions are reasonable and they are still mine. Yours differ in the places that matter most.
Put your actual numbers into the True Cost Calculator. The three inputs worth getting right, in order of how much they move the total: your property tax rate, which you can look up on your county assessor site rather than guess, your interest rate, and your maintenance assumption, where 1% is a starting point and an older house deserves more.
Then do the comparison that actually helps. Note the monthly payment the mortgage calculator gives you, and note the all in monthly figure the true cost calculator gives you. The gap between those two is the number to budget against. Everyone who has been surprised by homeownership was surprised by that gap.
Build your own 30 year total in the True Cost Calculator
Add taxes, insurance, maintenance, and HOA to see what the house really costs.
Related guides
The True Cost of Homeownership: Every Expense Beyond the Mortgage
A complete breakdown of homeownership costs beyond the mortgage payment -- property tax, insurance, maintenance, HOA, utilities, and opportunity cost.
Why Your Mortgage Barely Shrinks for Years (I Ran the Amortization Schedule)
Using a real $400,000 loan: how mortgage payments split between interest and principal, why you still owe 74% at the halfway point, and how to fight front-loading.
Renting vs Buying a Home in 2025: An Honest Financial Comparison
A data-driven analysis of renting vs buying -- the real costs of each, when buying wins financially, when renting makes more sense, and what the numbers actually show.
About the author
De Van Do has a background in technology and built VisualMortgage out of curiosity about making mortgage math transparent. De Van Do is not a licensed loan officer or mortgage broker -- for advice specific to your situation, consult a licensed mortgage professional. Read more about VisualMortgage.