Student loans and home buying exist in a permanent tension for millions of Americans in their late 20s and early 30s. You want to buy a house. You also have $30,000-$60,000 in federal student debt. Every extra dollar you put toward the student loans delays the down payment. Every dollar saved for the house is a dollar not reducing the debt. And while you're making this decision, mortgage rates are around 7%, student loan rates are around 6.5-7%, and your friends are buying houses with 5% down while you're trying to decide whether that's actually a good idea.
The math on this decision is real, it's calculable, and the right answer isn't the same for everyone — it depends on home prices in your market, the exact spread between your student loan rate and your mortgage rate, and a factor that most people underweight: the fundamental difference in what happens if your income changes. Here's the full analysis for a specific but representative scenario, followed by the framework for adjusting it to your numbers.
The Scenario
– Age: 28
– Income: $80,000 gross
– Student loan balance: $40,000 at 6.54% (2023-2024 federal graduate loan rate)
– Current student loan payment: $440/month (standard 10-year repayment, 6 years remaining)
– Down payment savings: $15,000 in a high-yield savings account
– Target home price: $250,000 (realistic for many Midwest, Southeast, and smaller-market buyers)
– Extra cash available each month: $600 (after all current expenses and minimum payments)
– Current rent: $1,200/month
The $600/month extra can go toward: (A) accelerating student loan payoff, (B) building the down payment, or some combination. We'll run three clean scenarios and compare the 10-year total cost for each.
Strategy A: Pay Off Student Loans First, Then Save Aggressively for the Down Payment
Timeline and Math
Add the $600/month extra to the current $440 student loan payment = $1,040/month toward student loans.
Student loan payoff timeline:
$40,000 at 6.54% with $1,040/month payment: paid off in approximately 43 months (3.6 years)
Total interest paid under Strategy A: approximately $8,200 (vs $17,600 over standard remaining term)
Interest saved vs minimum payments: approximately $9,400
After student loans are paid off (month 44):
Now redirect $1,040/month (former loan payment + extra) toward down payment
Already have $15,000 saved + small growth from HYSA
Target: 20% down = $50,000
Remaining needed: ~$33,000
Time to save $33,000 at $1,040/month: 32 months
Total time to house purchase: 43 + 32 = 75 months (6.25 years from today)
House purchased at approximately age 34.3
Down payment: $50,000 (20%)
Loan: $200,000 at 7.0%
Monthly payment (P&I): $1,331
PMI: $0
Total monthly housing: $1,331 + taxes/insurance
Equity on day one: $50,000 (20%)
Strategy B: Save for 20% Down First, Continue Minimum Loan Payments
Timeline and Math
Put the $600/month extra entirely toward the down payment. Continue minimum $440/month student loan payment.
Down payment savings timeline:
Currently have $15,000. Need $50,000.
Saving $600/month: need $35,000 more
Time to save $35,000 at $600/month: 58 months (4.8 years)
House purchased at approximately age 32.8
Down payment: $50,000 (20%)
Loan: $200,000 at 7.0%
Monthly payment: $1,331
PMI: $0
Student loans at time of purchase (month 58):
6 years of standard repayment already in progress; 58 months of minimum payments removes approximately $27,000 of the principal
Remaining student loan balance at purchase: approximately $17,000 (with ~18 months left)
Total interest paid on student loans over the full repayment: approximately $17,600
Strategy B vs Strategy A difference:
House purchased 16 months earlier under B vs A (age 32.8 vs 34.3)
Student loan total interest paid: $17,600 (B) vs $8,200 (A) — Strategy A saves $9,400 in loan interest
But Strategy B buys the house 16 months earlier — 16 months of $1,331/month mortgage vs $1,200/month rent = $131/month more expensive, but building equity instead of paying rent. Over 16 months: $2,096 in extra cost, but approximately $4,500-5,500 in equity built through principal reduction. Net: Strategy B comes out slightly ahead on this specific metric.
Strategy C: Buy Now With 5% Down, Continue Minimum Loan Payments
Timeline and Math
Already have $15,000. Need only $12,500 for 5% down on a $250,000 house. Can buy almost immediately.
Loan structure with 5% down:
Down payment: $12,500
Loan: $237,500 at 7.0%
Monthly payment (P&I): $1,580
PMI: approximately $158/month (0.8% annual on loan balance, typical for 5% down with good credit)
Total monthly housing cost under Strategy C:
$1,580 (P&I) + $158 (PMI) = $1,738/month — plus property taxes and insurance
This is $407/month more than the $1,331 payment under Strategy A or B (20% down)
How long does PMI last?
PMI cancels at 20% equity (LTV ratio reaches 80%). On a $237,500 loan at 7.0%, standard amortization builds equity slowly in the early years — reaching 80% LTV through payments alone takes approximately 9-10 years. Home price appreciation speeds this up significantly. If the home appreciates 4%/year, 20% equity is reached in approximately 4 years via combined appreciation + payments, allowing PMI cancellation.
Total PMI cost if cancelled at 4 years (48 months):
$158/month × 48 = $7,584 in PMI premiums paid
If PMI lasts the full standard term (9-10 years): $158 × 108 = $17,064
For the full breakdown of how PMI works, when it cancels automatically vs when you can request cancellation, and how to calculate your break-even point, see our detailed guide to PMI costs and cancellation timelines.
The 10-Year Total Cost Comparison
Cumulative Cost Through Month 120 (From Today)
To compare strategies fairly, we track total housing + student loan costs through month 120 (10 years from now), assuming the $250,000 home is purchased and held throughout:
Strategy A (pay off loans first, buy with 20% down at month 75):
– Months 1-43: rent $1,200/month + extra to loans: $51,600 rent + $8,200 loan interest
– Months 44-74: rent while saving for house: $37,200 rent
– Months 75-120: mortgage $1,331/month × 46 months: $61,226
– Student loan interest total: $8,200
10-year total: approximately $158,226
Strategy B (save for 20% down first, buy at month 58):
– Months 1-57: rent $1,200/month: $68,400 rent
– Months 58-120: mortgage $1,331/month × 63 months: $83,853
– Student loan interest total (full term): $17,600
10-year total: approximately $169,853
Strategy C (buy now with 5% down):
– Months 1-120: mortgage + PMI: ($1,580 + $158) × 48 months + $1,580 × 72 months: $83,424 + $113,760 = $197,184
– Student loan interest (continue minimum payments): approximately $17,600
– No rent paid (buying immediately)
10-year total: approximately $214,784 (offset by equity built, which is significant but doesn't reduce out-of-pocket cost)
10-year total cost ranking:
Strategy A: $158,226 — lowest total out-of-pocket
Strategy B: $169,853 — $11,627 more than A
Strategy C: $214,784 — $56,558 more than A (though with more equity built)
The credit score dimension matters too — a higher credit score at the time of mortgage application directly reduces the interest rate, and thus the monthly payment. Our analysis of how a 140-point credit score difference changes your mortgage payment over 30 years shows a difference of $468/month on a $300,000 loan. The student loan payoff in Strategy A also tends to improve DTI ratio (debt-to-income) — a cleaner DTI at mortgage application means better rate offers and more flexible underwriting.
The Factor Most People Underweight: Income Risk
Why Federal Student Loans Are Not Like Mortgage Debt
Federal student loans have income-driven repayment options. If you lose your job, your federal student loan payment drops to $0-$50/month under IBR (Income-Based Repayment) or SAVE plans. Your mortgage does not have this flexibility. Defaulting on a mortgage leads to foreclosure. Defaulting on student loans leads to wage garnishment and credit damage — serious, but survivable in a way that foreclosure isn't.
This asymmetry matters especially for Strategy C (buying with 5% down and a higher monthly payment) because the DTI burden is higher and the equity cushion is smaller. A homeowner with $237,500 in mortgage debt and $40,000 in student loans is carrying $277,500 in total debt service on an $80,000 income — that's a DTI above 40% if the student loans are at standard payment, which will already strain most mortgage underwriting standards.
Before committing to any strategy, use the student loan repayment strategy guide to confirm your federal loan eligibility for income-driven repayment plans. Knowing that your student loan payment has a $0 floor in a worst-case income scenario changes the risk calculus on how aggressively you can commit to a mortgage payment.
The Recommendation Framework
Which Strategy Fits Which Situation
Strategy A (pay off loans first) is best when:
– Your student loan rate is at or above current mortgage rates (6%+ on both)
– You have a stable, predictable income
– You can afford to rent for 5-6 more years without financial or lifestyle strain
– Your home market isn't rapidly appreciating (if home prices are rising 8%/year, waiting 6 years to buy costs you real appreciation)
Strategy B (save for 20% down) is best when:
– Your student loan rate is meaningfully below mortgage rates (4% student loan vs 7% mortgage)
– You want to buy in 4-5 years rather than 6+
– You want a clean balance sheet at mortgage application with no PMI
Strategy C (buy with 5% down now) is best when:
– Your local home market is appreciating rapidly (appreciation can quickly replace the equity you didn't put down)
– Your income is highly stable and growing
– Renting is not sustainable long-term (lease instability, family size growth, etc.)
– You have strong confidence in home price appreciation to cancel PMI within 3-4 years
For a broader look at 15-year vs 30-year mortgage structures and how the amortization schedule affects total interest paid over a home's ownership period, our .
The most important number in this entire analysis isn't the interest rate difference or the PMI cost — it's the extra monthly cash flow after the student loans are gone. Strategy A produces $1,040/month in freed-up cash flow at month 43 that can accelerate the down payment, increase retirement contributions, or provide financial flexibility that a tight mortgage payment under Strategy C doesn't allow. Financial decisions made under pressure — with a high monthly payment and limited margin — tend to produce worse outcomes than decisions made from a position of cash flow flexibility. A financial planning guide for millennials navigating student loans and home buying covers the full decision framework with examples across different loan amounts, home prices, and income levels — useful reading before committing to any path. For working through the actual numbers for your specific loan balance, interest rate, and target home price, a debt payoff and savings planner workbook creates a visual roadmap for each strategy so you can see the month-by-month trajectory before committing to a direction.