Buying Your First Home: What It Actually Costs
A first home comes down to four numbers: the down payment, the full monthly payment, closing costs, and the cash left afterward. Here's how to run them.
Key Takeaways
- The purchase price is the least useful number in a home purchase — what determines affordability is the full monthly payment and the total cash required to close.
- Principal and interest are only part of the monthly cost: property tax, insurance, mortgage insurance, and maintenance frequently add 40% or more on top.
- Closing costs typically run 2% to 5% of the purchase price and are paid in cash on top of the down payment, which surprises a large share of first-time buyers.
- Draining every account to reach a larger down payment leaves you owning a house with no buffer — the most common and most expensive first-time mistake.
Ask someone what their house cost and they will quote the purchase price. It is the number on the listing, the number they told friends, the number they remember. It is also close to useless for deciding whether they could afford it.
A home purchase resolves into four numbers, and the price is an input to all of them rather than one of them: the cash required for the down payment, the full monthly payment once every component is included, the closing costs due on the day, and the money left in your accounts after all of it clears. Get those four right and the decision becomes arithmetic. Get them wrong — usually by underestimating the second and forgetting the third — and you end up house-rich and cash-poor, which is a genuinely uncomfortable place to be.
Number One: The Down Payment
The down payment is the portion of the purchase price you pay upfront, with the mortgage covering the rest. It does two things: it reduces the amount borrowed, and it determines whether you will pay mortgage insurance.
Twenty percent is the figure everyone quotes, and it is a threshold rather than a rule. Below it, most lenders require mortgage insurance — a premium that protects the lender, not you, and typically adds somewhere between 0.3% and 1.5% of the loan amount per year to your costs. It can usually be removed once you have built sufficient equity, but until then it is a real monthly expense with no benefit to the borrower.
The trade-off is straightforward: a larger down payment means a smaller loan, a smaller monthly payment, and less interest over the life of the mortgage. A smaller down payment means keeping more cash. Which one is right depends heavily on the fourth number below.
Number Two: The Full Monthly Payment
This is where most affordability estimates go wrong, because people calculate the mortgage payment and stop there. The mortgage payment itself comes from a standard formula:
But principal and interest are one line among several. The full monthly housing cost is:
Property tax and homeowners insurance are commonly collected alongside the mortgage payment in an escrow account, which is why the lender's quoted figure is often higher than the raw mortgage calculation. Mortgage insurance applies below the equity threshold. Association or service charges apply to some properties. And maintenance applies to everything — a rough planning figure is 1% of the home's value per year, which on a $400,000 house is $4,000 annually whether or not anything breaks this year.
Number Three: Closing Costs
Closing costs are the fees required to complete the transaction, and they are paid in cash on top of the down payment. Typical range is 2% to 5% of the purchase price, covering:
- Lender fees: origination, underwriting, credit checks
- Appraisal and survey
- Title search, title insurance, and legal or conveyancing fees
- Recording and transfer taxes
- Prepaid property tax and insurance — often several months' worth collected in advance
On a $400,000 purchase that is $8,000 to $20,000, and it is due at the same moment as the down payment. A buyer who has saved precisely the down payment and nothing more does not have enough money to complete the purchase, which is a discovery best made months in advance rather than a week before closing.
Number Four: What Is Left Afterward
The number nobody calculates. After the down payment clears, the closing costs are paid, the movers are paid, and the immediate purchases are made — a fridge, curtains, a repair the survey flagged — what remains in your accounts?
If the answer is close to zero, the purchase has traded a liquid, flexible financial position for an illiquid one with an ongoing obligation attached. The first significant repair then goes on a credit card at 20% interest, which is a considerably worse outcome than having put down 15% instead of 20% and kept the difference.
A Worked Example
A $400,000 home, 10% down, 30-year mortgage at 6.5%:
| Cash required | Amount |
|---|---|
| Down payment (10%) | $40,000 |
| Closing costs (3%) | $12,000 |
| Moving and immediate purchases | $5,000 |
| Total cash needed | $57,000 |
The loan is $360,000. Running the payment formula with a monthly rate of 0.5417% over 360 payments gives principal and interest of approximately $2,275. Then the rest:
| Monthly component | Amount |
|---|---|
| Principal and interest | $2,275 |
| Property tax (1.1% of value) | $367 |
| Homeowners insurance | $125 |
| Mortgage insurance (0.5% of loan) | $150 |
| Maintenance set-aside (1% of value) | $333 |
| Total monthly cost | $3,250 |
Two observations. The mortgage payment is 70% of the true monthly cost — anyone budgeting on the $2,275 figure alone is understating by nearly a thousand dollars a month. And the buyer needs $57,000 in cash, of which only $40,000 is the down payment everybody talks about.
The mortgage insurance line is worth noting separately: $150 a month, or $1,800 a year, buying the borrower nothing. Reaching 20% equity — through payments, appreciation, or a larger initial down payment — removes it.
How Much You Can Actually Afford
Lenders commonly apply two ratios: housing costs at or below 28% of gross monthly income, and total debt payments at or below 36%.
Applied to the example, the $2,917 that a lender would count as housing cost — principal, interest, tax, insurance, and mortgage insurance, excluding maintenance — implies gross income of roughly $10,400 a month, or about $125,000 a year.
Treat that as a ceiling, not a target. Lender approval reflects the probability that they get paid; it says nothing about whether the payment leaves room for retirement contributions, holidays, or a job change. A useful cross-check is to run the full monthly cost through your existing budget: if it consumes far more than the needs bucket in a 50/30/20 split can absorb, the number is too high regardless of what a lender says.
Common First-Time Mistakes
- Budgeting on the mortgage payment alone. As above, the true carrying cost is routinely 40% higher.
- Forgetting closing costs. They arrive as cash at the worst possible moment for cash.
- Emptying every account for a larger down payment. Owning a home with no buffer is a fragile position, and repairs do not wait for you to rebuild savings.
- Borrowing the maximum approved. Lender ceilings assume your circumstances never change.
- Ignoring the time horizon. Transaction costs on both purchase and sale mean short holding periods frequently lose to renting, whatever the local market has been doing.
- Skipping the survey to win a competitive bid. Waiving inspection to make an offer more attractive transfers every hidden defect to the buyer.
Before You Start Looking
Run your actual numbers first — what you earn, what you spend, what you have. If you have not built a budget from real statements, do that before speaking to a lender, because the affordability question is unanswerable without it.
Then work backwards: set the cash floor you will not breach, subtract closing costs and moving expenses from your available savings, and see what down payment remains. That figure, combined with a monthly cost you can carry comfortably rather than maximally, defines your price range. Shopping in that range means the arithmetic works before you fall in love with a house — which is a far better order to do it in.
