{"uid":"cap_qSTjydo-8mQUrHAPQRdN8","slug":"finance-calculators-mortgage-affordability-28-36-rule-3614c48d","name":"Finance Calculators: Mortgage Affordability (28/36 Rule)","description":"Home price you can afford under the 28/36 rule from income, monthly debts, down payment, rate and term.","url":"https://finance-calculators.x402tookit.com/mortgage-affordability?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET"],"type":"string"},"queryParams":{"type":"object","required":["annual_income","annual_rate_pct"],"properties":{"years":{"type":"integer","description":"Term in years, default 30"},"down_payment":{"type":"number","description":"Cash down payment, default 0"},"annual_income":{"type":"number","description":"Gross annual household income"},"monthly_debts":{"type":"number","description":"Other monthly debt payments, default 0"},"annual_rate_pct":{"type":"number","description":"Mortgage rate in percent"},"tax_insurance_monthly":{"type":"number","description":"Property tax plus insurance per month, default 0"}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object","properties":{"asOf":{"type":["null","string"]},"source":{"type":["null","string"]},"maxLoan":{"type":["null","number"]},"reasons":{"type":["array","null"],"items":{"type":"string"}},"summary":{"type":["null","string"]},"verdict":{"type":["null","string"]},"degraded":{"type":["boolean","null"]},"limitedBy":{"type":["null","string"]},"disclaimer":{"type":["null","string"]},"notChecked":{"type":["array","null"],"items":{"type":"string"}},"checkPayment":{"type":["null","number"]},"maxPurchasePrice":{"type":["null","number"]},"grossMonthlyIncome":{"type":["null","number"]},"maxMonthlyPrincipalInterest":{"type":["null","number"]}}}}}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.02","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.02/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.02","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.02","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_LOSj_txHkJswazI-HnQ7P","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.02","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Calculates the maximum home purchase price and loan amount you can afford using the 28/36 debt-to-income rule, given income, debts, down payment, rate, and term.","exampleAgentPrompt":"Using the 28/36 rule, what's the most expensive home I can afford if I make $95,000 a year, have $600 in monthly debts, a $40,000 down payment, a 6.8% mortgage rate over 30 years, and $350/month in property taxes and insurance?","exampleUseCases":[{"title":"First-time buyer budget check","prompt":"I earn $80,000 a year, have about $400 in monthly car and student loan payments, $25,000 saved for a down payment, and I'm seeing rates around 7.1%. Can you tell me the most expensive home I can realistically afford on a 30-year mortgage, using the 28/36 rule?"},{"title":"Dual-income household home search","prompt":"My partner and I have a combined household income of $155,000, we carry $1,100 in monthly debts, and we've saved $80,000 for a down payment. With a 6.5% mortgage rate on a 30-year term and roughly $500/month in taxes and insurance, what's the maximum purchase price we should be looking at?"},{"title":"Pre-offer affordability sanity check","prompt":"We're about to make an offer on a house. Our gross annual income is $120,000, we have $900/month in existing debts, $50,000 down payment, and the rate we're quoted is 7.25% for 30 years. What's the maximum home price the 28/36 rule says we can afford, and what would limit us — the front-end or back-end ratio?"}],"resultDescription":"Returns the maximum loan amount and purchase price you can afford, the maximum allowable monthly principal-and-interest payment, your gross monthly income, which constraint (front-end 28% or back-end 36%) limits you, a verdict and plain-language summary, plus a disclaimer. Optionally includes checks not performed and degraded-mode flags.","failureModes":["Missing required parameters (annual_income or annual_rate_pct) returns a 4xx error","Unrealistic inputs (zero income, negative rate) may yield zero or null maxLoan","If the back-end ratio is already exceeded by existing debts alone, maxLoan may be 0 with an explanatory reason","Service downtime may return a 5xx error; retry after brief delay"],"whenToPreferThis":"Use this endpoint when you need a quick, rules-based mortgage affordability figure grounded in the widely-accepted 28/36 debt-to-income standard. It is ideal for pre-search budget setting, offer sanity checks, or financial planning tools that need a deterministic affordability ceiling. Prefer it over generic loan calculators when you need to factor in existing monthly debts and want both front-end (housing) and back-end (total debt) ratio analysis in a single call.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-30T00:34:28.524Z","isFirstParty":false,"canonicalSlug":"finance-calculators-mortgage-affordability-28-36-rule-3614c48d"}