Planning Your Down Payment
The Down Payment Challenge
Saving for a down payment is often the biggest financial hurdle for prospective homebuyers. In many markets, the down payment requirement can be $50,000 to $100,000 or more—often representing years of disciplined savings. Understanding how long it will take to reach your goal allows you to set realistic timelines, adjust your savings rate if needed, or reconsider your target home price. This calculator projects your savings trajectory using compound interest, showing you exactly when you'll be ready to purchase.
Down payment amounts vary significantly by loan type. FHA loans require just 3% down, making homeownership accessible to first-time buyers with limited savings. Conventional loans typically require 5–20% down, with anything below 20% triggering Private Mortgage Insurance (PMI), which adds to monthly costs. Many buyers aim for 20% down to avoid PMI and get better interest rates, while others with tight timelines or limited savings opt for smaller down payments and accept PMI temporarily, planning to remove it through future equity buildup.
The Savings Formula with Compound Interest
The future value of savings with regular deposits and compound interest follows this formula:
where:
- = future value (target amount)
- = current principal (savings to date)
- = monthly interest rate (annual rate ÷ 12)
- = monthly deposit amount
- = number of months
Down Payment Percentages Explained
3% Down (FHA Loans): FHA mortgages, backed by the Federal Housing Administration, require just 3% down, with no maximum loan limit in most areas. However, FHA loans require mortgage insurance for the life of the loan (or 11 years minimum). Total monthly costs include the principal/interest payment plus insurance premium. FHA loans have lower credit score requirements and more flexible underwriting, making them popular with first-time buyers.
5–10% Down (Conventional, Mortgage Insurance Required): Conventional loans with down payments below 20% require Private Mortgage Insurance (PMI). PMI protects the lender if you default. The cost is typically 0.5–1.5% of the loan amount annually, added to your monthly payment. PMI can be removed once you reach 20% equity through principal paydown (usually 5–10 years of payments).
20% Down (The Gold Standard): A 20% down payment eliminates PMI entirely, significantly reducing your monthly payment. This has historically been the benchmark for mortgage qualification, though today's lenders accept lower percentages. Reaching 20% down reduces your total loan amount, saves tens of thousands in insurance costs, and often qualifies you for better interest rates.
25%+ Down (Premium Position): Down payments above 20% place you in an extremely strong position. Lenders view these borrowers as very low-risk, often offering the best available rates. You're building substantial equity immediately and protecting yourself against negative equity (owing more than the home is worth).
Worked Example: First-Time Homebuyer
Marcus wants to buy a $350,000 home and aim for a 20% down payment to avoid PMI:
- Target Home Price: $350,000
- Down Payment Goal (20%): $70,000
- Current Savings: $25,000
- Remaining to Save: $45,000
- Monthly Savings: $2,000
- Interest Rate: 4.5% APY (0.375% monthly)
Using the compound interest formula:
Month 1: $25,000 + $2,000 + interest ≈ $27,094
Month 12: $25,000(1.00375)^12 + $2,000×15.95 ≈ $58,847
Month 23: $25,000(1.00375)^23 + $2,000×31.75 ≈ $70,025 ≈ GOAL REACHED
Marcus will reach his $70,000 down payment goal in approximately 23 months (just under 2 years) with his current savings rate and interest earnings.
Variables Affecting Your Timeline
Savings Rate: Increasing monthly savings by even $500 can accelerate your timeline by 10–12 months. Before buying, review your budget ruthlessly: can you cut expenses, pick up a side gig, or redirect bonuses toward down payment savings?
Interest Rate: Today's high-yield savings accounts earn 4–5% annually, much higher than traditional banks (0.01%). This makes saving in a HYSA critical: the interest differential alone can add thousands to your down payment without increasing your actual savings discipline.
One-Time Windfalls: Tax refunds, work bonuses, inheritance, or family gifts can dramatically accelerate your timeline. Even a $10,000 windfall can shorten your savings period by 5–6 months.
Home Price Changes: If home prices in your market increase faster than you're saving, your target down payment amount creeps higher. Conversely, a market slowdown might mean less competition, better pricing, and an achievable down payment sooner.
Comparison Table: Down Payment Scenarios
| Down Payment % |
Home Price $350K |
Loan Amount |
PMI Monthly (0-1.2%) |
Timeline to Save* |
| 3% (FHA) |
$10,500 |
$339,500 |
$340–$407 (for life) |
5 months |
| 5% |
$17,500 |
$332,500 |
$233–$399/mo |
8 months |
| 10% |
$35,000 |
$315,000 |
$147–$315/mo |
15 months |
| 15% |
$52,500 |
$297,500 |
$44–$149/mo |
21 months |
| 20% |
$70,000 |
$280,000 |
$0 (No PMI) |
23 months |
| 25% |
$87,500 |
$262,500 |
$0 (No PMI) |
31 months |
*Timeline assumes $25K current savings, $2K monthly, 4.5% APY. PMI ranges vary by lender and credit score.
Strategy: PMI Removal Planning
Rather than waiting 2+ years to save 20%, many buyers purchase with 10% down and plan to eliminate PMI through equity buildup. With a $350,000 home at 10% down ($35,000), you borrow $315,000. In 4–8 years of principal payments (depending on interest rate), you'll build 20% equity and can request PMI removal. This strategy works if:
- Your home doesn't depreciate significantly
- You can afford the slightly higher monthly payment (with PMI)
- You commit to staying in the home long enough for PMI removal to make financial sense
- You qualify for a loan with removable PMI (not all do)
Limitations and Assumptions
- This calculator assumes steady monthly savings and doesn't account for irregular bonuses or windfalls (except the lump sum input).
- Interest is calculated monthly; actual savings account compounding may vary slightly.
- This calculator does not account for closing costs (typically 2–5% of home price), which are separate from down payment.
- Home prices are assumed static; the calculator doesn't adjust for market appreciation or depreciation.
- PMI costs are estimates and vary by lender, loan type, credit score, and down payment percentage.
- Inflation effects on your savings purchasing power are not included.
- Loan approval depends on income, credit, and other factors not modeled here.
Closing Costs: The Hidden Expense
Many first-time buyers save for the down payment but are surprised by closing costs at the purchase. These typically run 2–5% of the home price (on a $350,000 home, that's $7,000–$17,500). Closing costs include appraisal fees, title insurance, lender fees, escrow, recording fees, and attorney fees. Some buyers negotiate with the seller to cover closing costs or are willing to put down less and roll closing costs into the loan. Factor these into your savings planning.