PITI + Utilities: Your True Monthly Cost, Line by Line

The short answer: your true monthly cost is PITI plus five more lines

The real monthly cost of a house is the mortgage payment (principal, interest, taxes, insurance, and mortgage insurance if you owe it) plus the lines no lender collects: electricity, heating fuel, water, internet, and a maintenance reserve. On the worked example below, a $375,000 house that a payment calculator prices at $2,133 a month actually runs about $3,560 a month once every line is on the ledger. That is not pessimism; it is just the whole list.

This guide builds that ledger line by line, with a national-average source or a stated assumption for each entry, so you can rebuild it for any house you are about to offer on. If you want the shorter story of why the calculator number and the real number diverge, that is covered in what mortgage calculators leave out. This is the companion piece: the full budget, built from the bottom up.

The lender's lines: PITI plus PMI

The payment your lender collects has up to five parts, and they bundle into one autopay. Principal and interest are set by the loan. Taxes and insurance are set by the house and usually flow through an escrow account. Mortgage insurance rides along until you have enough equity.

Here is each line on a $375,000 house with 10 percent down ($37,500), leaving a $337,500 loan at an assumed 6.5 percent for 30 years. Every figure below is an estimate; your county, insurer, and lender set the real ones.

Principal and interest: $2,133. The standard amortization formula on $337,500 at 6.5 percent over 360 months. This is the number most calculators show, and the only one determined purely by the loan.

Property taxes: $344. An assumed 1.1 percent effective rate on the full $375,000 price, or $4,125 a year escrowed monthly. Rates vary enormously by county, and the listing's tax line is often the previous owner's bill. Many counties reassess at sale, so apply your county's rate to your price, not the portal's number.

Homeowners insurance: $189. Bankrate's Hidden Costs of Homeownership study puts the national average premium at $2,267 a year, and premiums have been rising fastest in storm and wildfire states. A quote on the actual address, ordered before you offer, replaces this average with a real number.

Mortgage insurance: $169. Below 20 percent down on a conventional loan, PMI is part of the payment. At an illustrative 0.6 percent annual rate on the $337,500 loan, that is $2,025 a year. Your actual rate depends on credit score and down payment.

Total so far: $2,835 a month. That is the lender's-view payment, the one your debt-to-income ratio is computed from, and it is already $702 above the bare calculator number.

The house's lines: what utilities really run

Now the lines that never appear on a mortgage statement but leave your checking account every month anyway.

Electricity: $144. The U.S. Energy Information Administration puts the average residential electric bill at $144 a month in 2024, based on an average 16.5 cents per kilowatthour and 865 kilowatthours a month. The spread is wide: Hawaii averaged $213 a month while Utah averaged $89, and hot-summer states use far more air conditioning. A bigger house than your current place will likely bill bigger too.

Heating fuel: $60, stated assumption. Homes heat with natural gas, electricity, propane, or heating oil, and EIA's Winter Fuels Outlook re-forecasts what each costs every season because the number moves with weather and wholesale prices. If the home heats with electricity, this line folds into the one above; if it heats with gas, propane, or oil, it is a separate bill concentrated in winter. We assume $60 a month averaged across the year. The seller's actual bills beat any national figure.

Water and sewer: $83. The EPA's WaterSense program reports the average family spends more than $1,000 a year on water. Usage runs about 82 gallons per person per day at home, so household size moves this line more than house size does. Irrigation can multiply it in dry regions.

Internet: $126, stated assumption. We carry the same $126 a month used in our calculator-gap guide, in line with national studies of internet and cable costs. Yours may be half that; it will not be zero.

Maintenance reserve: $313. The classic rule of thumb is 1 to 2 percent of the home's value per year. At 1 percent of $375,000, that is $3,750 a year, or $313 a month. You will not spend it monthly; you will spend it in lumps (a water heater here, a roof section there), which is exactly why it belongs in the budget as a reserve rather than a surprise.

The full ledger, one table

Two gaps are worth naming. The calculator-to-lender gap is $702: the escrowed lines a bare payment calculator skips. The lender-to-true gap is another $726: the ownership lines nobody collects. A buyer budgeting from the $2,133 calculator number is planning around 60 percent of the real figure.

Which lines move when the price moves

This is the part that matters when you are shaping an offer. Principal, interest, and PMI scale with the loan, so a lower price or a bigger down payment shrinks them. Property taxes scale with the price. But insurance, utilities, and maintenance scale with the house itself: its size, age, systems, and location. Offer $10,000 less on this example and your payment drops by about $71 a month at the same down payment percentage, counting the principal and interest, tax, and PMI changes together (with the down payment itself dropping $1,000); the electricity, water, and maintenance lines do not move at all.

That has a practical corollary: two houses at the same price can carry very different true monthly costs. A newer, smaller, well-insulated house at $375,000 can cost meaningfully less per month than an older, larger one at the same price, before either of you negotiates a dollar.

At 20 percent down ($75,000), the same house runs $1,896 in principal and interest with no PMI, for a lender's-view payment of about $2,429. The ownership lines stay put, so the true cost is still roughly $3,155. The down payment moved three lines out of ten.

How to build this ledger for a real house

Work from documents, not averages, wherever you can. County assessor page for the tax rate applied to your offer price. An insurance quote on the address. The lender's actual PMI rate. The seller's utility bills for the last twelve months, which your agent can request. Then add the maintenance reserve honestly, using 1 to 2 percent of value or the age of the big systems as your guide.

This ledger is exactly what the offer builder assembles when you point it at an address: loan, taxes, insurance, PMI, utilities, and maintenance, line by line, so the monthly number you plan around belongs to the house and not just the loan. The same discipline applies to your upfront cash, where the down payment is one line among several; the cash to close calculator itemizes that side, and how much cash you really need to buy a $400,000 house walks a full example.

The point is not that owning costs more than a calculator says. It is that every line is knowable before you offer, and a buyer who knows all ten lines negotiates differently than one who knows three.

Estimates, not appraisals · not legal or financial advice.