Affordability / DTI (USA)
Estimate safe payment capacity and implied loan size from debt-to-income (DTI) targets.
Inputs
Affordability / DTI
DTI budget limits
What limits you?
Binding rule: Back-end DTI
Housing ratio at limit: 23.5%
Total debt ratio at limit: 36.0%
Given payment check
How your entered housing payment compares with the modeled affordability budget.
This payment is a bit above the target budget and may feel tight depending on reserves.
📖 How affordability and DTI work
DTI means debt-to-income ratio. It compares your monthly obligations to your gross monthly income. In mortgage planning, lenders often use debt-to-income limits to judge whether a payment is reasonable.
Affordability is not just about the home price you want. Lenders usually look at your housing payment relative to income, and your total debt load relative to income. Those two lenses are commonly called front-end DTI and back-end DTI.
Front-end DTI
Housing payment only as a percentage of gross monthly income.
Back-end DTI
Housing payment plus your existing debts as a percentage of gross monthly income.
Affordable payment
The calculator uses the tighter of those two rules to estimate a realistic housing budget.
💵 What the affordability budget really means
The affordability budget is not a promise from a lender. It is a planning estimate showing how much monthly housing payment could fit within your chosen DTI targets.
The modeled max loan P&I backs out taxes and insurance, because those costs consume part of your housing budget but do not increase your loan principal.
The implied loan amount is especially useful for testing rate scenarios. If rates rise, the same monthly payment supports a smaller principal.
🔍 Why affordability results change quickly
Rates move principal power
Even if your payment budget stays flat, higher mortgage rates reduce the loan amount that payment can support.
Taxes and insurance matter
Higher property tax, homeowners insurance, flood insurance, or HOA-style costs leave less room for principal and interest.
Existing debts tighten the cap
Car loans, student loans, credit cards, and personal loans directly reduce the housing budget available under back-end DTI.
Guidelines differ by lender
Actual loan approval can vary by loan program, reserves, credit score, down payment, and underwriting overlays.
❓ Frequently asked questions
What is a good DTI ratio?
Many planning models start near 28% front-end and 36% back-end, but loan programs can allow more or less depending on borrower strength.
Why is my affordable loan amount lower than expected?
Usually because rate, taxes and insurance, or existing debts are consuming more of the monthly housing budget than expected.
Should I rely only on the implied loan amount?
No. Use it as a planning estimate, then compare with down payment, cash to close, PMI, and your own comfort level.