Planning tool
Estimate a monthly housing payment from a home price, down payment, loan term and an interest rate you choose. Results are estimates, not quotes.
Last reviewed: September 30, 2026
Planning tool
Fields marked * are required. All math runs in your browser. InterWest does not see, save or track your numbers.
Loan amount = home price − down payment. Monthly principal and interest uses the standard fixed-rate amortization formula: loan × r ÷ (1 − (1 + r)^−n), where r is your annual rate ÷ 12 and n is the number of monthly payments. At 0% the loan is divided evenly across the payments.
Taxes and insurance are your yearly estimates divided by 12. HOA dues are added as entered.
Mortgage insurance (PMI or FHA mortgage insurance), VA funding fees, USDA guarantee fees, closing costs, prepaid items, and future changes to taxes or insurance are not included. Adjustable-rate loans are not modeled.
InterWest doesn't show an advertised rate here. Actual rates depend on market conditions, the loan program, credit, loan amount, property and other factors. Only a lender's official Loan Estimate shows the terms you're offered.
The calculation happens in your browser. Nothing you type is sent to InterWest, saved or used to contact you.
Explore
Estimates are a starting point. These guides explain what comes next.
How a preapproval differs from a calculator estimate.
Budgeting, programs and questions for a first purchase.
Compare conventional, FHA, VA, USDA and Idaho Housing paths.
Talk through your own numbers with the InterWest team.
Official references
Program information can change. These official resources support the specific contexts described below; confirm current rules before relying on them.
Explains the official Loan Estimate form, closing costs and estimated cash to close.
Explains rate locks and how to compare Loan Estimates.
A useful next step
Want to know how real pricing and program rules change the estimate? Let's talk.
