Down Payment & PMI Calculator

Your down payment does more than shrink the loan — at 20% it eliminates private mortgage insurance (PMI), a recurring cost that protects the lender, not you. This calculator shows how your down payment changes the loan, the monthly payment, and whether PMI applies.

20% or more avoids PMI.

Down payment amount$40,000
Loan amount$360,000
Principal & interest / mo$2,275.44
Estimated PMI / mo (under 20%)$150.00
Total monthly (P&I + PMI)$2,425.44
Down payment percentage10.0%

How this calculator works

The down payment is a percentage of the price; the rest is financed:

down = price × down%  |  loan = price − down

The principal-and-interest payment comes from the standard amortization formula. If your down payment is under 20%, lenders require PMI. We estimate it at roughly 0.5% of the loan per year (a typical midpoint — actual PMI ranges by credit and loan-to-value), shown as a monthly add-on.

Why 20% is the magic number

At 20% down your loan-to-value ratio is 80%, the threshold at which PMI is waived. PMI typically costs 0.3–1.5% of the loan annually and adds nothing to your equity, so reaching 20% — or removing PMI later once you’ve built 20% equity — directly lowers your housing cost.

Frequently asked questions

What is PMI and why do I pay it?
Private mortgage insurance protects the lender if you default. It's required on most conventional loans when you put down less than 20%. It's a cost to you with no benefit to you, which is why avoiding or removing it matters.
How do I get rid of PMI?
Put 20% down to avoid it entirely, or once your loan balance falls to ~80% of the home's value (through payments or appreciation), you can usually request its removal; it often auto-terminates at 78%.
Is a bigger down payment always better?
It lowers your loan, payment, and interest, and can avoid PMI — but don't drain your emergency fund to do it. Balance the down payment against keeping cash reserves; the home affordability and mortgage calculators help you weigh it.
Is the PMI figure here exact?
No — it's an estimate (~0.5%/yr of the loan). Actual PMI depends on your credit score, loan-to-value, and insurer. Use it as a ballpark and confirm with your lender.