US Mortgage Calculator

com.usmortgagecalcPublished by usmortgagecalc.comOfficial publisherv1.0.1Updated Oct 24, 2026

US mortgage calculator and amortization API with 50-state property tax, PMI, and affordability data.

VerifiedStreamable HTTPWeb executableFinanceData & Analytics

Overview

AI-generated overview

A remote US mortgage calculator that lets an assistant compute payments, amortization, PMI, taxes, affordability, refinancing and rent-versus-buy comparisons.

What you can do
Calculate full monthly housing costs, lifetime totals and payoff timing for a US mortgage, optionally using a state's average property tax rate. Break down repayment with monthly or yearly amortization and see how extra principal shortens the loan. Estimate mortgage insurance for conventional, FHA, VA and other programmes, including upfront premiums and cancellation points. Compute property tax, affordability limits under the 28/36 ratios, refinance break-even and closing costs. Compare two to five loan scenarios by monthly payment and lifetime cost, and compare renting with buying on net wealth. Look up state property tax rules and list states with average rates and median home values.
When to use it
Useful when answering US home-buying questions: estimated payments, loan comparisons, PMI and tax costs, how much house a buyer can afford, whether to refinance, and rent-versus-buy trade-offs.
Requirements
A remote streamable HTTP endpoint; no package, account, API key or environment variable is declared. Network access to the provider's endpoint is needed.
Before you install
Results are estimates based on inputs and state averages, and the rent-versus-buy result is described as highly sensitive to appreciation assumptions. No authentication is declared, so avoid sending personal financial details you would not share with a third-party service.

Installation

In SourceWeft

  1. Open US Mortgage Calculator in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Web executable via Streamable HTTP. Remote servers run from the web runtime once configured in a workspace.

Use with an agent

Paste this prompt into Claude Code, Codex, Cursor or another agent — or into SourceWeft chat. The agent reads this server's install guide, shows you its publisher, endpoint and sign-in, and adds it to your client once you agree. Keys never go into a command.

Read https://sourceweft.com/mcp/com.usmortgagecalc%2Fmortgage/install.md and connect the MCP server it describes to my client. Before changing any config, show me its publisher, endpoint and sign-in method and wait for my OK. Never put an API key in a command or in a file I would commit; ask me where it should come from.

Read the install guide the agent follows

Other MCP clients

Add this to your client's mcpServers config.

{
  "mcpServers": {
    "us-mortgage-calculator": {
      "type": "http",
      "url": "https://www.usmortgagecalc.com/mcp"
    }
  }
}

Tools

11

calculate_mortgage

Calculate a monthly mortgage payment

Full monthly housing cost for a US mortgage: principal and interest, property tax, homeowners insurance, mortgage insurance and HOA dues, plus lifetime totals and payoff timing. Pass a state name to use that state's average property tax rate. This is the right tool for 'what would my payment be on a $400,000 house'.

ParametersstateloanTypehomePricerequiredmonthlyHoaloanTermYearsannualInsurancedownPaymentPercentmonthlyExtraPrincipalpropertyTaxRatePercentannualInterestRatePercent

calculate_amortization

Build an amortization schedule

Payment-by-payment breakdown of how a loan is repaid, showing the split between principal and interest and the falling balance. Use granularity 'monthly' for the first years in detail, 'yearly' for a whole-term overview. Also reports how much sooner extra principal pays the loan off.

ParametersstateloanTypehomePricerequiredmonthlyHoagranularityloanTermYearsannualInsurancedownPaymentPercentmonthlyExtraPrincipalpropertyTaxRatePercentannualInterestRatePercent

calculate_pmi

Calculate mortgage insurance

Mortgage insurance for any US loan programme, including the upfront charges most calculators omit. Conventional: monthly PMI and the month it cancels at 80% and 78% loan-to-value. FHA: the 1.75% upfront premium, monthly MIP, and whether it runs for the life of the loan or ends after 11 years. VA: the funding fee, tiered by down payment and prior use, and waivers. USDA: guarantee and annual fees.

ParametersloanTypehomePricerequiredcreditScoreloanTermYearsvaSubsequentUsedownPaymentPercentmonthlyExtraPrincipalvaExemptFromFundingFeeannualInterestRatePercent

calculate_property_tax

Estimate property tax

Annual and monthly property tax for a home, using a state's average effective rate. Also returns how that state ranks nationally and how its rate compares with the national average. For the mechanics behind the number — assessment basis, caps, exemptions, appeal deadlines — use get_state_mortgage_rules.

ParametersstaterequiredhomePricerequired

calculate_affordability

Work out how much house someone can afford

Maximum affordable home price from income, existing debt payments and available down payment, using the 28/36 qualifying ratios. Reports which of the two ratios is the binding constraint, which is the actionable part: a buyer limited by the back-end ratio can raise their budget by clearing debt, one limited by the front-end ratio cannot.

ParametersstatemonthlyHoaloanTermYearsannualInsuranceannualGrossIncomerequireddownPaymentAmountrequiredbackEndRatioPercentmonthlyDebtPaymentsfrontEndRatioPercentpropertyTaxRatePercentannualInterestRatePercent

calculate_refinance

Evaluate a refinance

Whether refinancing is worth it: the new payment, monthly saving, and how many months it takes to recover closing costs. Also compares lifetime interest, which catches the common trap where a lower payment costs more overall because the term was reset.

ParametersclosingCostsrequirednewTermYearscurrentBalancerequiredfinanceClosingCostsnewAnnualRatePercentrequiredcurrentAnnualRatePercentrequiredcurrentRemainingTermMonthsrequired

estimate_closing_costs

Itemise closing costs

Line-by-line buyer closing costs — lender fees, title, appraisal, transfer taxes, prepaid escrow — plus total cash needed at the table including the down payment. Marks which items are worth shopping for and which are fixed by the county, and adds the FHA upfront premium, VA funding fee or USDA guarantee fee where they apply.

ParametersstateloanTypehomePricerequiredescrowMonthsannualInsurancevaSubsequentUsedownPaymentPercenttransferTaxPercentpropertyTaxRatePercentvaExemptFromFundingFee

calculate_rent_vs_buy

Compare renting with buying

Compares renting and buying on net wealth rather than on monthly payment, accounting for equity, appreciation, maintenance, selling costs, and the return a renter earns on money not spent on a down payment. Returns the year buying overtakes renting. The result is highly sensitive to the appreciation and investment-return assumptions, which are returned alongside it.

ParametersstatehomePricerequiredmonthlyHoamonthlyRentrequiredloanTermYearsyearsToCompareannualInsurancedownPaymentPercentsellingCostPercentpropertyTaxRatePercentinvestmentReturnPercentannualMaintenancePercent+3 more

compare_loans

Compare loan options side by side

Compares two to five loan scenarios and reports which is cheapest by monthly payment and which by lifetime cost, separately, because they frequently are not the same loan. Use for 15-year versus 30-year, FHA versus conventional, competing lender quotes, or with and without discount points.

Parametersscenariosrequired

get_state_mortgage_rules

Look up a state's property tax rules

How property tax actually works in one state: how assessed value is derived, any statutory growth cap, the billing cycle, named exemptions such as homestead, the filing deadline, who hears appeals and the window to file, notable county variation, and a link to the state's own tax authority. Use this when the question is about mechanics or deadlines rather than a dollar amount.

Parametersstaterequired

list_states

List all 50 states with property tax rates

Every US state with its average effective property tax rate, median home value and estimated annual tax. Sortable, so it answers 'which states have the highest property taxes' directly. Call this to discover valid state names for the other tools.

ParameterslimitordersortBy

Version history

1
  1. v1.0.1LatestSep 16, 2026

Score

83% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 daysRequired25 pts
  • Auth declaredRequired10 pts
  • Tools listedRequired15 pts
  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts

    Declare a GitHub repository with a README, or serve resource_documentation in the OAuth protected-resource metadata.

  • LicenseNot applicable

    A hosted service is used under its provider's terms, so no license is expected here. This check is left out of the percentage.