Calculate your monthly payment, total interest, and true cost of your home loan.
Home Price ($)
$
Down Payment ($)
$
Annual Interest Rate (%)
%
Loan Term
Monthly Payment
$0.00
Principal + Interest only
Loan Amount
—
after down payment
Total Paid
—
over loan term
Total Interest
—
cost of borrowing
Down %
—
of home price
Annual Cost
—
P+I per year
Interest %
—
of total paid
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How Monthly Mortgage Payments Are Calculated
Your monthly P&I payment uses the standard amortization formula:
M = P × [r(1+r)^n] / [(1+r)^n − 1]
M = monthly payment · P = loan principal
r = monthly rate (annual rate ÷ 12) · n = total payments
What's NOT included in this calculation
Property taxes: typically 1–2% of home value per year
Home insurance: avg $1,200–$2,400/year
PMI: ~0.5–1.5%/year if down payment < 20%
HOA fees: varies by community
The 28% rule
Financial advisors suggest your monthly mortgage payment shouldn't exceed 28% of your gross monthly income. On a $100,000 salary, that's a max payment of ~$2,333/month.
Mortgage FAQ
Use the 28/36 rule: housing costs should be ≤28% of gross income, total debt ≤36%. On $80,000/year ($6,667/mo gross), max housing payment is ~$1,867/mo, supporting roughly a $280,000–$320,000 loan at 7%.
A 15-year mortgage has higher monthly payments but saves tens of thousands in interest and builds equity faster. A 30-year has lower payments, more flexibility, and lets you invest the difference. The 30-year rate is typically 0.5–1% higher.
Yes — significantly. On a $320,000 30-year loan at 7%, paying just $100/month extra saves ~$40,000 in interest and cuts 4+ years off the loan. Extra payments go directly to principal, reducing future interest.