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What is the 3/3/3 Rule for Home Buying? A Simple Affordability Guide



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Sqrd Media
Sqrd Media
September 4, 2026 | 6 Minute Read
When you start shopping for a house, figuring out your true comfort zone can feel like navigating a maze of conflicting financial advice. Lenders might tell you that you qualify for a $600,000 mortgage, but your bank account tells a very different story.
That is where popular budgeting benchmarks come in, most notably, the 3/3/3 Rule for home buying.
As salary-based loan officers at City Creek Mortgage, our job isn’t to max out your borrowing limit so a lender makes a bigger profit. Our goal is to make sure you land in a home you love without becoming “house poor.” In this guide, we’ll break down what the 3/3/3 rule is, how it measures up against traditional mortgage guidelines, and how to evaluate your real-world buying power.

What Is the 3/3/3 Rule in Home Buying?

The 3/3/3 Rule is a popular rule of thumb designed to keep homebuyers from overstretching their finances. It breaks down your home purchase into three simple parameters:
  1. Rule 1: Your home price should not exceed 3x your gross annual income.
  2. If your household earns $120,000 a year pre-tax, the rule suggests targeting a maximum purchase price of $360,000 ($120,000 $\times$ 3).
  3. Rule 2: You should have at least 30% of the home’s price in cash savings.
  4. This 30% is split into two pools: 20% allocated for a standard down payment (to avoid PMI) and 10% kept liquid as a buffer for closing costs, moving expenses, and an immediate emergency fund.
  5. Rule 3: Your total monthly housing payment should not exceed 30% of your gross monthly income.
  6. This includes Principal, Interest, Property Taxes, Homeowners Insurance, and any HOA fees (PITI).
While the 3/3/3 rule is a great gut-check for financial discipline, market realities, especially in high-growth states like Utah, mean that many buyers need to adapt these numbers to fit their local landscape.

How to Determine Your Affordable Home Price Range

Beyond popular internet rules, mortgage underwriting uses specific guidelines to measure what you can afford.

What percentage of my income should go towards my mortgage?

Most financial experts recommend capping your total monthly housing cost between 28% and 30% of your gross (pre-tax) monthly income.
Underwriter guidelines frequently rely on the 28/36 Rule:
  • 28% Front-End Cap: Your mortgage payment (including taxes and insurance) shouldn’t exceed 28% of pre-tax income.
  • 36% Back-End Cap: Your total monthly debt obligations—mortgage plus student loans, car payments, and minimum credit card payments—should not exceed 36% of pre-tax income.

How do I calculate my maximum home buying budget?

To calculate your baseline budget, start with your gross monthly income, apply your target ratio, and subtract your existing recurring debts.
The Calculation:
(Gross Monthly Income x Target Debt Ratio) – Existing Monthly Debts = Max Monthly Mortgage Payment
For example, if your household makes $9,000/month gross and has $600 in student loan and auto payments, a 36% total debt threshold leaves you with $2,640/month available for your total housing payment ($9,000 x 0.36 = $3,240 – $600 = $2,640).

What factors should I consider when determining how much home I can afford?

  • Net Take-Home Pay: Gross income looks great on paper, but taxes, health insurance, and retirement contributions reduce what actually hits your bank account.
  • Lifestyle & Discretionary Costs: Childcare, groceries, travel, and hobbies are never reflected on a credit report, but they dictate your quality of life.
  • Future Life Changes: Are you planning a career shift, going back to school, or starting a family? Budget for where your life is heading, not just where it is today.

Understanding Mortgage Options and Affordability

The loan structure you select directly dictates how far your monthly budget will stretch.

What types of mortgages are available, and how do they affect my buying power?

Different mortgage programs have distinct down payment requirements and insurance rules that alter your monthly costs:
  • Conventional Loans: Require as little as 3% down. Private Mortgage Insurance (PMI) is required if you put down less than 20%, but it drops off automatically once you reach 20% equity.
  • FHA Loans: Allow down payments as low as 3.5% with lower credit score thresholds, but require Mortgage Insurance Premiums (MIP) that typically remain for the entire life of the loan.
  • VA Loans: Available to eligible military members and veterans, offering 0% down options with no ongoing monthly mortgage insurance.
  • USDA Loans: Offer 0% down financing for homes in designated rural and suburban areas for income-eligible buyers.

How does the interest rate influence how much home I can afford?

Interest rates are the largest variable in your monthly purchasing power. Because early mortgage payments are heavily weighted toward interest, a shift of just 1% in interest rates can swing your purchasing power by roughly 10% to 12%.
Example: $400,000 Loan (30-Year Fixed, Principal & Interest Only)
• At 5.5% Interest Rate: ~$2,271 / month
• At 6.5% Interest Rate: ~$2,528 / month  (+$257/mo difference)
• At 7.5% Interest Rate: ~$2,797 / month  (+$526/mo difference)

Evaluating Financial Readiness for Home Buying

A home purchase requires balancing your upfront cash with ongoing long-term reserves.

How much should I save for a down payment?

While the 3/3/3 rule recommends putting 20% down, the average first-time homebuyer actually puts down 6% to 7%.
  • 20% Down: Eliminates monthly mortgage insurance and lowers your loan balance, but takes significantly longer to save.
  • 3% to 5% Down: Gets you into a home much faster, allowing you to begin building equity sooner, though it results in a higher monthly payment and temporary PMI.

What is the impact of my credit score on home affordability?

Your credit score dictates your interest rate tier and your PMI costs. A buyer with a 760 credit score will receive lower interest rates and significantly cheaper PMI premiums than a buyer with a 640 credit score taking out the exact same loan amount.

What are the additional costs associated with buying a home that I need to consider?

Beyond your monthly mortgage principal and interest, your budget must account for:
  1. Closing Costs: Lender fees, title insurance, appraisal, and escrow pre-paids typically total 2% to 4% of the loan amount out-of-pocket at closing.
  2. Property Taxes & Homeowners Insurance: Escrowed into your monthly payment and subject to annual rate adjustments.
  3. HOA Dues: Monthly or quarterly fees charged in managed communities that directly impact your DTI ratio.
  4. Maintenance Reserves: Setting aside 1% of the home’s value annually for ongoing upkeep and repairs.

Utilizing Tools and Resources to Calculate Affordability

Calculating your numbers manually is a good baseline, but interactive tools give you instant line-by-line clarity.

Where can I find a reliable mortgage calculator?

Avoid basic web calculators that only calculate principal and interest. City Creek Mortgage provides a transparent Affordability Calculator that breaks down exact estimates for taxes, insurance, and interest rates specific to your area.

Frequently Asked Questions

Is the 3/3/3 rule still realistic in today’s housing market?

It depends on your local market. In high-cost-of-living areas, limiting your purchase price to 3x your annual income can be difficult. Many buyers stretch to 3.5x or 4x income if they have minimal debt, while compensating by maintaining a strong emergency buffer.

How do rising property taxes and insurance affect my affordability over time?

Even if you hold a fixed-rate mortgage, your monthly payment can increase over time if local property taxes increase or homeowners insurance premiums rise. Your lender will adjust your monthly escrow payment annually to cover these changes.

How do HOA fees impact how much home I can afford?

Lenders count HOA dues dollar-for-dollar into your front-end housing ratio. A $300/month HOA fee reduces your mortgage borrowing capacity by roughly $40,000 to $50,000 in total loan amount.

Bottom Line

The 3/3/3 rule offers a clear, conservative framework to protect you from getting overextended: keep your price around 3x your income, hold 30% in total savings/reserves, and cap your payment at 30% of your gross pay. Use it as a helpful guide, but remember that your real lifestyle budget matters most.
Ready to see exact rates and payment scenarios tailored to your actual numbers? Check out our Affordability Calculator to explore live Utah rates with zero pressure.
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