Down Payment Calculator
How much down payment do you need — and how long to save it? Calculate your down payment amount, loan size, monthly payment, and see the real cost difference between 5%, 10%, and 20% down.
Try a scenario
How to Use This Calculator
Tab "How Much"
Enter the home price, your intended down payment percentage, the mortgage rate your lender has quoted, and the loan term. The result shows your exact down payment amount, loan size, estimated monthly principal and interest payment, and whether PMI applies.
Tab "Savings Timeline"
Enter your target down payment, how much you have already saved, and your planned monthly contribution. The calculator tells you how many months until you reach your goal — and the target calendar date.
Tab "5% vs 10% vs 20%"
Enter one home price, one mortgage rate, and one term. The calculator shows a side-by-side table comparing all three down payment levels: down amount, loan amount, monthly payment, PMI cost, and total interest over the life of the loan. Adjust the PMI rate field to match your lender's quoted rate.
The Formulas
Down = Home price × (Down % / 100)
Loan = Home price − Down
Monthly mortgage payment (amortisation):
PMT = P × r_m × (1 + r_m)^n / ((1 + r_m)^n − 1)
where P = loan amount, r_m = annual rate / 12, n = total months
Total interest over loan term:
Total interest = (PMT × n) − P
Savings timeline:
Months to goal = (Target − Current savings) / Monthly contribution
Monthly PMI estimate:
PMI/month = (Loan amount × Annual PMI rate) / 12
PMI applies when down payment is below 20% of home price.
All calculations use standard mortgage mathematics. No country-specific tax rates, stamp duty, or government fees are applied. Results are pre-tax estimates.
Worked Examples
Example 1 — $500K home at 20% down, 6% rate, 30 years
The "traditional" 20% down payment on a $500,000 home with a 6% fixed-rate 30-year mortgage.
With 20% down you avoid PMI entirely. Your monthly payment covers principal and interest only. Over 30 years you pay $463K in interest — nearly the value of the loan itself.
Example 2 — Same home at 10% down (with PMI)
Same $500K home, same 6% rate, but only 10% down. Now you need PMI until your equity reaches 20%.
You need $50,000 less upfront — but pay roughly $487/mo more until PMI is cancelled. The trade-off: you could buy 3+ years earlier while saving toward 20%.
Example 3 — Savings timeline: $30K saved, need $100K, saving $2,000/month
A buyer has $30,000 saved and needs $100,000 for a 20% down payment on a $500K home.
At $2,000/month it takes 35 months (just under 3 years) to save the remaining $70,000. Earning interest in a high-yield savings account could shave a few months off this timeline.
The 20% Down Payment Myth
Where the 20% rule comes from
The 20% benchmark exists because lenders historically required it to avoid PMI — Private Mortgage Insurance, which protects the lender if you default. Below 20% equity, lenders view the loan as higher risk. PMI covers that risk, so they allow smaller down payments.
But "20% or wait" is not the only rational choice. Many financial situations make 5% or 10% down the smarter move.
When a smaller down payment makes sense
You buy years earlier. If it takes 3 extra years to save from 10% to 20%, you miss 3 years of equity building, potential price appreciation, and the stability of homeownership. In markets where prices rise 4%–6% per year, waiting can cost more than the PMI.
You preserve liquid savings. Putting every dollar into a down payment can leave you with no emergency fund. A home has ongoing costs — repairs, maintenance, appliances. Being "house poor" is a real risk.
Your income is growing. If your salary is rising, you may be able to pay off the extra loan balance faster than expected, cancelling PMI ahead of schedule.
When 20% down really is worth it
If you plan to stay in the home long-term, can comfortably save to 20%, and want the lowest possible monthly payment from day one — 20% down is excellent. You avoid PMI entirely, reduce total interest paid, and start with meaningful equity.
The key is running the real numbers. Use the "5% vs 10% vs 20%" tab to compare the exact monthly and total cost for your home price and rate.
PMI is not forever
In most markets, once your equity reaches 20% of the original purchase price — through payments, extra principal paydown, or appreciation — you can request PMI cancellation. Lenders are legally required to cancel PMI automatically once your loan-to-value ratio reaches 78% based on your original amortisation schedule (in the US under the Homeowners Protection Act). The actual rules vary by country and loan type.
Beyond the Down Payment: What Else to Budget
Closing costs
Closing costs typically run 2%–5% of the purchase price and must be paid upfront — on top of the down payment. They include lender origination fees, appraisal, title search, title insurance, escrow fees, and prepaid items (first year homeowners insurance, property tax escrow). On a $500,000 home, budget $10,000–$25,000 for closing costs.
Moving and immediate expenses
Professional movers, storage, new furniture, painting, and small repairs add up quickly. Budget at least $5,000–$10,000 for move-in expenses on a typical purchase.
Home maintenance reserve
Financial planners commonly recommend setting aside 1%–2% of the home's value per year for maintenance. On a $500K home that is $5,000–$10,000 per year, or $415–$833 per month — a real cost not captured in the mortgage payment.
Property taxes and insurance
Your lender will typically escrow property taxes and homeowners insurance into your monthly payment. These vary widely by location and are not included in the calculator's principal and interest estimate.