Understand this tool
Put a mortgage payment in context
- What the concept means
- A mortgage is a loan secured by real property; its scheduled payment commonly amortizes principal and interest over a long term.
- Why it exists
- This page estimates the principal-and-interest portion after subtracting a down payment from the purchase price.
- When to use it
- Use it to compare price, down payment, rate, and term before obtaining lender-specific estimates.
- What the result means—and does not mean
- The displayed monthly result is P&I only. A household’s full housing payment can also include property tax, homeowners insurance, mortgage insurance, association dues, utilities, maintenance, and escrow adjustments.
From purchase price to housing cost
The down payment reduces the amount borrowed, but it also uses cash that could have other purposes. Loan-to-value compares the mortgage balance with the property value and can affect underwriting or insurance requirements.
Escrow is an account a servicer may use to collect tax and insurance amounts alongside principal and interest. Because those items can change, the total monthly payment need not remain equal to the calculator’s P&I result.
Key concepts
Key concepts
- Down payment
- Purchase funds paid upfront rather than borrowed.
- Loan principal
- Price minus the modeled down payment.
- Principal and interest (P&I)
- The amortizing loan portion of a payment.
- Loan-to-value (LTV)
- Loan balance divided by property value.
- Escrow
- Funds collected for items such as tax and insurance.
- Total housing cost
- The broader recurring and irregular cost of owning the home.
Method or process
Calculation method
From purchase price to housing cost
The down payment reduces the amount borrowed, but it also uses cash that could have other purposes. Loan-to-value compares the mortgage balance with the property value and can affect underwriting or insurance requirements.
Escrow is an account a servicer may use to collect tax and insurance amounts alongside principal and interest. Because those items can change, the total monthly payment need not remain equal to the calculator’s P&I result.
Formula or rule
principal = price − down payment; P&I uses the amortized-loan formulaCompare the concepts
P&I and the complete monthly outlay
| Measure | Included | Not necessarily included |
|---|---|---|
| Calculator payment | Principal and interest | Tax, insurance, dues, maintenance |
| Total housing outlay | All applicable ownership costs | Depends on the property and location |
Common mistakes
Common mistakes
- Reading P&I as the full monthly cost.
- Ignoring closing and maintenance costs.
- Comparing rates without equal terms and fees.
Edge cases and limits
Edge cases and limits
- Adjustable-rate mortgages cannot be represented by one permanent rate.
- Interest-only, balloon, and biweekly products need different models.