{"success":true,"version":"v1","request":{"tool":"get_calculator_schema","calculator_id":"debt-to-income"},"result":{"entity_type":"calculator","id":"debt-to-income","calculator_id":"debt-to-income","canonical_url":"https://tttkmbb.com/finance/debt-to-income","name":"Debt-to-Income Ratio Calculator","title":"Debt-to-Income (DTI) Ratio Calculator – Front-End and Back-End Ratios with Lender Guidelines","category":"finance","category_name":"Finance","tool_name":"calculate_debt_to_income_ratio","featured_mcp_tool":false,"description":"Computes the back-end debt-to-income ratio (all monthly debt payments including housing divided by gross monthly income) and the front-end ratio (housing payment alone), and compares them with the 28/36 guideline and the 43 % qualified-mortgage benchmark.","use_when":"You want to check whether a proposed mortgage or other loan fits typical lender DTI limits, or how much monthly debt capacity remains.","do_not_use_when":"You need to know how long it takes to pay a balance off (use debt-payoff), or the amount of a down payment (use down-payment).","inputs":[{"name":"gross_monthly_income","label":"Gross monthly income","type":"number","required":true,"max":100000000,"exclusive_min":0,"description":"Total pre-tax income per month (salary, bonuses, other verifiable income).","example":6000},{"name":"monthly_debts","label":"Monthly debt payments","type":"number_list","required":false,"description":"Minimum monthly payments on non-housing debts: car loans, student loans, credit-card minimums, alimony. Omit if you use other_monthly_debt.","example":[400,250,150]},{"name":"other_monthly_debt","label":"Other monthly debt","type":"number","required":false,"default":0,"min":0,"max":100000000,"description":"Additional non-housing debt payments not itemised in monthly_debts (or the whole total if you have it).","example":0},{"name":"housing_payment","label":"Housing payment","type":"number","required":false,"min":0,"max":100000000,"description":"Proposed or current monthly housing cost: rent, or mortgage principal, interest, taxes, insurance and HOA (PITI). Enables the front-end ratio.","example":1500}],"outputs":[{"name":"total_monthly_debt_payments","label":"Total monthly debt payments","type":"number","decimals":2,"description":"Sum of monthly_debts + other_monthly_debt + housing_payment."},{"name":"back_end_dti_percent","label":"Back-end DTI","type":"number","unit":"%","decimals":2,"description":"total_monthly_debt_payments / gross_monthly_income × 100."},{"name":"front_end_dti_percent","label":"Front-end DTI","type":"number","unit":"%","decimals":2,"description":"housing_payment / gross_monthly_income × 100 (only when housing_payment is given)."},{"name":"assessment","label":"Assessment","type":"string","decimals":4,"description":"Band of the back-end ratio: Good (≤ 36 %), Acceptable (36–43 %), High (43–50 %) or Very high (> 50 %)."},{"name":"max_housing_payment_at_28_percent","label":"Max housing payment at 28 %","type":"number","decimals":2,"description":"0.28 × gross_monthly_income (front-end guideline)."},{"name":"max_total_debt_at_36_percent","label":"Max total debt at 36 %","type":"number","decimals":2,"description":"0.36 × gross_monthly_income (conservative back-end guideline)."},{"name":"max_total_debt_at_43_percent","label":"Max total debt at 43 %","type":"number","decimals":2,"description":"0.43 × gross_monthly_income (qualified-mortgage benchmark)."},{"name":"remaining_capacity_at_43_percent","label":"Remaining capacity at 43 %","type":"number","decimals":2,"description":"max_total_debt_at_43_percent − total_monthly_debt_payments (negative when already above 43 %)."}],"input_schema":{"type":"object","properties":{"gross_monthly_income":{"description":"Total pre-tax income per month (salary, bonuses, other verifiable income).","type":"number","maximum":100000000,"exclusiveMinimum":0,"examples":[6000]},"monthly_debts":{"description":"Minimum monthly payments on non-housing debts: car loans, student loans, credit-card minimums, alimony. Omit if you use other_monthly_debt.","type":"array","items":{"type":"number"},"examples":[[400,250,150]]},"other_monthly_debt":{"description":"Additional non-housing debt payments not itemised in monthly_debts (or the whole total if you have it).","type":"number","minimum":0,"maximum":100000000,"default":0,"examples":[0]},"housing_payment":{"description":"Proposed or current monthly housing cost: rent, or mortgage principal, interest, taxes, insurance and HOA (PITI). Enables the front-end ratio.","type":"number","minimum":0,"maximum":100000000,"examples":[1500]}},"additionalProperties":false,"required":["gross_monthly_income"]},"output_schema":{"type":"object","properties":{"total_monthly_debt_payments":{"description":"Sum of monthly_debts + other_monthly_debt + housing_payment.","type":"number"},"back_end_dti_percent":{"description":"total_monthly_debt_payments / gross_monthly_income × 100. Unit: %.","type":"number","x-unit":"%"},"front_end_dti_percent":{"description":"housing_payment / gross_monthly_income × 100 (only when housing_payment is given). Unit: %.","type":"number","x-unit":"%"},"assessment":{"description":"Band of the back-end ratio: Good (≤ 36 %), Acceptable (36–43 %), High (43–50 %) or Very high (> 50 %).","type":"string"},"max_housing_payment_at_28_percent":{"description":"0.28 × gross_monthly_income (front-end guideline).","type":"number"},"max_total_debt_at_36_percent":{"description":"0.36 × gross_monthly_income (conservative back-end guideline).","type":"number"},"max_total_debt_at_43_percent":{"description":"0.43 × gross_monthly_income (qualified-mortgage benchmark).","type":"number"},"remaining_capacity_at_43_percent":{"description":"max_total_debt_at_43_percent − total_monthly_debt_payments (negative when already above 43 %).","type":"number"}}},"formula":"back_end_dti = (Σ monthly_debts + other_monthly_debt + housing_payment) / gross_monthly_income × 100; front_end_dti = housing_payment / gross_monthly_income × 100","method":"Bands follow common US underwriting practice: the 28/36 rule (housing ≤ 28 %, all debt ≤ 36 %) and the 43 % back-end cap of the original 2014 Qualified Mortgage rule; since 2021 the General QM definition uses a price-based test, but 43 % remains a widely used benchmark and Fannie Mae allows up to 50 % with compensating factors. Utilities, groceries and insurance are not debts.","sources":[{"name":"CFPB – What is a debt-to-income ratio?","url":"https://www.consumerfinance.gov/ask-cfpb/what-is-a-debt-to-income-ratio-en-1791/","type":"government","retrieved_at":"2026-09-24"},{"name":"CFPB – Ability-to-Repay and Qualified Mortgage Standards (Regulation Z)","url":"https://www.consumerfinance.gov/rules-policy/final-rules/ability-to-repay-and-qualified-mortgage-standards-under-the-truth-in-lending-act-regulation-z/","type":"government","retrieved_at":"2026-09-24"},{"name":"Investopedia – Debt-to-Income (DTI) Ratio: What's Good and How to Calculate It","url":"https://www.investopedia.com/terms/d/dti.asp","type":"reference","retrieved_at":"2026-09-24"}],"freshness":{"type":"static","max_age_seconds":null,"note":"Deterministic formula with fixed constants; results never go stale. Inputs supplied by the caller determine the output."},"examples":[{"name":"6,000 income, debts 400/250/150, housing 1,500","inputs":{"gross_monthly_income":6000,"monthly_debts":[400,250,150],"housing_payment":1500},"expected":{"total_monthly_debt_payments":2300,"back_end_dti_percent":38.33,"front_end_dti_percent":25,"assessment":"Acceptable (36–43 %)","max_housing_payment_at_28_percent":1680,"max_total_debt_at_36_percent":2160,"max_total_debt_at_43_percent":2580,"remaining_capacity_at_43_percent":280},"url":"https://tttkmbb.com/api/v1/calculate/debt-to-income?gross_monthly_income=6000&monthly_debts=400%2C250%2C150&housing_payment=1500"},{"name":"8,000 income, 1,600 total debt, no housing given","inputs":{"gross_monthly_income":8000,"other_monthly_debt":1600},"expected":{"total_monthly_debt_payments":1600,"back_end_dti_percent":20,"assessment":"Good (≤ 36 %)","max_total_debt_at_43_percent":3440},"url":"https://tttkmbb.com/api/v1/calculate/debt-to-income?gross_monthly_income=8000&other_monthly_debt=1600"}],"faq":[{"q":"Gross or net income?","a":"Lenders use gross (pre-tax) income, so enter pay before taxes and deductions; using take-home pay overstates the ratio."},{"q":"Which payments count as debt?","a":"Recurring obligations that appear on a credit report or court order: loans, credit-card minimum payments, leases, child support. Utilities, phone plans, insurance and groceries are excluded."}],"tags":["debt to income","dti ratio","front-end ratio","back-end ratio","28/36 rule","mortgage qualification"],"related":[{"calculator_id":"mortgage-payment","reason":"Compute the PITI housing payment to enter here."},{"calculator_id":"down-payment","reason":"Loan amount and PMI for the purchase."},{"calculator_id":"debt-payoff","reason":"Clear a balance to lower the ratio."}],"links":{"html":"https://tttkmbb.com/finance/debt-to-income","markdown":"https://tttkmbb.com/finance/debt-to-income.md","json":"https://tttkmbb.com/finance/debt-to-income.json","api":"https://tttkmbb.com/api/v1/calculate/debt-to-income","schema":"https://tttkmbb.com/api/v1/calculators/debt-to-income","openapi":"https://tttkmbb.com/openapi.json","mcp":"https://tttkmbb.com/mcp"},"version":"v1","updated_at":"2026-09-24"},"timestamp":"2026-09-24T01:50:59Z"}