Mortgage Calculator
Estimate your monthly principal & interest payment, compare 15- vs. 30-year terms, and see total interest paid over the life of the loan — at any purchase price, rate, and down payment combination.
Get Started in 3 Steps
How to Use the Mortgage Calculator
Enter Your Purchase Details
Input your home price, down payment amount or percentage, annual interest rate, and loan term (15 or 30 years).
Review Your Payment Breakdown
See your monthly P&I payment, total interest over the loan life, and a full year-by-year amortization schedule.
Model Different Scenarios
Adjust rate, term, or down payment to instantly compare how each variable changes your monthly cost and total interest.
Mortgage Calculator
Estimate your monthly payment instantly
*Estimate only. Actual costs may vary.
How do I calculate my monthly mortgage payment?
Your monthly mortgage payment is calculated using the loan amount, interest rate, and loan term with a standard amortization formula. On a $450,000 home with 10% down ($405,000 loan) at 6.75% for 30 years, your monthly principal & interest payment would be $2,627.
Best for: First-time buyers, move-up buyers comparing terms, anyone budgeting for a home purchase
How It Works
Understanding the Mortgage Calculator
This calculator uses the standard amortization formula to compute your monthly principal and interest (P&I) payment based on three inputs: loan amount (purchase price minus down payment), annual interest rate, and loan term. It also generates a full year-by-year amortization schedule showing how each payment splits between principal and interest over the life of the loan.
Worked example: You're buying a $500,000 home in Portland, Oregon with 20% down ($100,000). Your loan amount is $400,000 at 6.50% for 30 years. The calculator shows a monthly P&I of $2,528, total interest of $510,177 over 30 years. Switch to a 15-year term and the payment rises to $3,484 — but total interest drops to $227,176, saving you $283,001.
Use this tool before you start house hunting to find the maximum price that fits your monthly budget. Pair it with our DTI Calculator to confirm your payment fits within lender guidelines, and our Conventional & PMI Calculator if your down payment is below 20%.
Ready to apply?
Numbers look right? Explore our Conventional Loans page for eligibility details, rates, and next steps.
About This Calculator
What the Mortgage Calculator is For
The starting point for any home purchase. Enter your purchase price, down payment, interest rate, and loan term to see your monthly P&I payment and a full amortization schedule. Use it to compare 15-year vs. 30-year terms side by side, stress-test how a half-point rate change affects your payment, and find the purchase price ceiling that fits your monthly budget — before you start touring homes.
Common Use Cases
- First-time buyers sizing up what they can afford
- Comparing 15-yr vs. 30-yr total interest cost
- Modeling rate sensitivity across different rate scenarios
Ready to turn numbers into a loan?
Or call 503-966-9255Common Questions
Mortgage Calculator — Frequently Asked Questions
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From the Blog
Further Reading
VineyardFinancing a 30-Acre Vineyard Estate in Grass Valley, California: Conventional vs. Ranch Home Loans vs. Ag Loans on a $2.29M Nevada County Wine Property
A real-world walkthrough of how to finance a 30-acre established vineyard estate in Grass Valley, Nevada County — 18 acres of producing vines planted in 2002, a Craftsman home, a six-suite office building, a 1,500 sq ft barn, a separately-metered tent building generating rental income, a 20,000-gallon Gunite pool with studio pool house, NID irrigation water, and AG zoning across three parcels. We compare the three viable loan products on the same property: Conforming Conventional vs. standard residential Jumbo, our Ranch Home Loans jumbo, and our true Ag loan options. The decision depends on whether the buyer is occupying the residence and farming at hobby scale, scaling commercial wine production under a use-permit-driven venue plan, or buying the property as an investment to rent out — each path leads to a different product.
EquestrianFinancing a 19-Acre Equestrian Estate in Lincoln, California: Conventional vs. Ranch Home Loans vs. Ag Loans on a $1.5M Sierra Foothills Horse Property
A real-world walkthrough of how to finance a 19.34-acre luxury equestrian estate in Lincoln, Placer County — five-stall barn, arena, round pen, NID-irrigated hay production, two wells, two septics, and barn-loft ADU potential. We compare the viable loan products on the same property: Conforming Conventional vs. standard residential Jumbo, our Ranch Home Loans jumbo, and our true Ag loan options. The 'right' answer isn't the cheapest rate — it's the structure that respects the acreage, the hay income, the improvements, and the buyer's plans for the loft above the barn. Here's how Sierra Foothills equestrian buyers actually navigate the financing decision.
Investment LoansConventional vs. DSCR vs. DSCR Interest-Only: How a Brookings Oregon STR Borrower Picked the Right Investment-Property Loan
A high-performing short-term rental near Brookings, Oregon. $500K loan on a property valued north of $1.5M. Vested individually — not in an LLC — with rental income flowing straight to Schedule E. We walked the borrower through four side-by-side options: a Conventional 30-year fixed, a DSCR 30-year fixed, a DSCR 10-year interest-only with a 40-year term, and ultimately a Conventional 15-year fixed. Same rate range across the three 30-year options, similar closing costs, but the right answer wasn't the cheapest payment — it was the loan that aligned with how this borrower actually plans to operate the property. Here's the full deep-dive analysis, the math at Freddie Mac PMMS averages, and exactly why a Conventional 15-year fixed won.
All calculator results are estimates for informational purposes only and do not constitute a loan commitment or guarantee of any specific rate or terms. Actual loan terms will depend on creditworthiness, property type, and market conditions. Lumen Mortgage Corporation · NMLS #1498678 · Licensed in Oregon & California · 920 SW 6th Ave, Suite 1200, Portland, OR 97204.