How to Calculate Your First Home Budget: A Step-by-Step Guide for Buyers

Buying your first home is exciting, but before you start browsing listings or scheduling tours, you need a clear budget.

Whether you’re buying a home in Phoenix or a condo in Baltimore, knowing how to calculate your first home budget helps you shop confidently, avoid financial strain, and make stronger offers. From upfront costs to monthly expenses and long-term planning, this Redfin guide will teach you how to determine what you can realistically afford.

Why calculating your home budget matters

Your home budget determines more than just your price range. It influences:

• The homes you should focus on
• How much cash you need upfront
• Whether your monthly payment will feel manageable
• How competitive your offer can be

Without a clear budget, buyers often experience financing surprises, delayed closings, or buyer fatigue from touring homes outside their comfort zone.

Step 1: Calculate your gross monthly income

Start with your gross monthly income, which is your income before taxes and deductions.

Include:

• Salary or hourly wages
• Bonuses or commissions
• Side income
• Rental or investment income

If your income fluctuates, calculate an average over the past one to two years.

Step 2: Understand your debt-to-income ratio

Lenders use your debt-to-income ratio, or DTI, to determine how much you can borrow.

There are two types:

Front-end DTI – This includes your future housing costs only.

Back-end DTI – This includes housing costs plus other debts such as student loans, car payments, and credit cards.

Most lenders prefer:

• Front-end DTI under 28%
• Back-end DTI under 36 – 43%

For example, if your gross monthly income is $6,000, your total monthly debts including your future mortgage payment typically should not exceed about $2,160 to $2,580, depending on the loan program. Some loan programs allow higher DTIs depending on credit score and other factors.

Step 3: Follow the 28/36 rule as a starting point

A common budgeting guideline is the 28/36 rule.

• Spend no more than 28% of gross income on housing
• Spend no more than 36% of gross income on total debt

If you earn $5,500 per month, 28% equals $1,540. That would be your maximum recommended housing payment, including principal, interest, property taxes, homeowners insurance, and HOA fees if applicable.

Keep in mind this is a guideline, not a requirement. Your comfort level matters more than hitting a specific percentage.

Step 4: Estimate your total monthly housing payment

Your mortgage payment includes more than just principal and interest. Budget for the full monthly housing cost, often called PITI:

• Principal
• Interest
• Property taxes
• Homeowners insurance

You may also need to include:

• Private mortgage insurance if your down payment is under 20 percent
• HOA dues
• Flood insurance in certain areas

This full number is what determines affordability, not just the loan amount.

Step 5: Calculate your upfront costs

Your first home budget must account for upfront expenses, not just monthly payments.

Down payment

Many first-time buyers put down between 3% – 10%, depending on the loan type. Some loan programs require as little as 3% down, while others such as VA loans may require no down payment.

Closing costs

Closing costs typically range from 2% – 5% of the purchase price and may include:

• Loan origination fees
• Appraisal
• Title insurance
• Escrow fees
• Prepaid taxes and insurance

On a $350,000 home, closing costs could range from $7,000 to $17,500.

Moving and setup costs

Do not forget:

• Moving expenses
• Utility deposits
• Initial repairs
• Furniture or appliances

These costs add up quickly and should be part of your total savings goal.

Step 6: Review your monthly budget honestly

Before committing to a home price, evaluate your current spending.

Ask yourself:

• How much do I save each month?
• Will I still be able to build an emergency fund?
• Am I planning major life changes such as starting a business or changing jobs?

Just because a lender approves you for a certain amount does not mean you should spend that much.

Zach Buchenau of Be The Budget says he encourages first-time buyers “to use the lender’s approval number as a high-end starting point, then build their budget from scratch based on their actual life. 

“Your lender doesn’t know your life goals – having a baby, taking a yearly vacation, retiring at 50 –  but those things define your real financial life. If you buy below what you qualify for and give yourself some margin, you can always move up in a few years if you need to. Digging yourself out of a mortgage that’s suffocating your lifestyle is a much harder problem to solve both financially and emotionally.”

Step 7: Leave room for homeownership costs

According to Zach, the commonly overlooked costs are small, recurring expenses that stack up: lawn care, metro district or HOA fees, small repairs or a washer that floods your laundry room six months in. “I tell people to budget 1% – 2% of the home’s value per year, depending on the age of the home, for maintenance alone,” Zach says. “If that number, plus your mortgage, taxes, and insurance, makes you uncomfortable, that’s your sign the house is too expensive.”

Budget for:

• Maintenance and repairs
• Landscaping
• Pest control
• Appliance replacement
• Higher utility bills

A common rule of thumb is to set aside 1% of the home’s value per year for maintenance. For a $400,000 home, that is about $4,000 annually.

Step 8: Get pre-approved to confirm your range

After calculating your personal comfort zone, speak with a lender and get pre-approved. A pre-approval:

• Confirms how much you qualify for
• Provides an estimated interest rate
• Strengthens your offer when you find a home

This step turns your estimated budget into a realistic purchase range.

Example: Calculating a first home budget

Let’s say you earn $6,000 per month before taxes and have $400 in monthly debt.

Using the 36% rule:

• 36 percent of $6,000 equals $2,160
• Subtract $400 in debt
• That leaves $1,760 for housing

If current rates put your estimated mortgage payment at $1,750 per month, including taxes and insurance, that may be within your target range.

You would then calculate how much home price corresponds to that payment based on interest rates and your down payment.