Your rate hides in the formula
Every $100/month supports wildly different principals: ~£16k at 6.5% over 30 years vs ~£57k over 5 years. Same payment, totally different loan muscle.
Payment power
Loan Affordability Calculator
Inputs
Before tax. If “annual” is selected we’ll convert to monthly.
Housing share of gross income (PITI + HOA/PMI if applicable).
All debts incl. housing.
We’ll add this to the max loan to estimate a home price.
We subtract these from your allowed housing payment.
PMI as annual % of loan (e.g., 0.5%). We’ll divide by 12.
| Name | Monthly Payment | Actions |
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Results
Max affordable housing/loan payment
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We’ll show which DTI cap limited affordability.
Mortgage mode
Max principal & interest payment: —
Estimated max loan amount: —
Estimated max home price (loan + down): —
Assumes fixed-rate, level payments. Taxes/insurance/HOA/PMI were subtracted from the allowed housing payment.
Inputs echo
— income / month
Other debts: — • Front cap: — • Back cap: —
How this Affordability Calculator Works (and how to use it calmly)
Affordability is really a question about cash flow: “How much payment can I carry each month without stretching?” Lenders often look at two ratios. The front-end DTI caps the share of gross income that can go to housing alone (mortgage principal & interest, property tax, homeowners insurance, HOA, and—when relevant—PMI). The back-end DTI caps housing plus all other monthly debt payments (loans, card minimums, BNPL instalments, etc.). This tool uses both caps and picks the stricter result.
In Mortgage mode, we subtract taxes/insurance/HOA/PMI (the non-P&I parts of housing) from your allowed housing payment to find a maximum principal-and-interest payment. We then invert the fixed-rate amortization formula—given the interest rate and term— to estimate the largest loan that payment can support. Finally, we add your down payment to estimate a plausible home price target. If your down payment is small, PMI (private mortgage insurance) may apply; you can include it as an annual percent for a conservative estimate.
In Generic mode, we ignore property-specific add-ons and simply treat the allowed payment as the maximum loan payment, again inverting the amortization formula to estimate a max principal for your rate and term. This is handy for auto or personal loans.
Tips for better estimates
- Sense-check DTI caps: Many households aim for housing near ~28–31% and total debts under ~36–43% of gross income. Use numbers that fit your situation.
- Don’t forget other costs: Utilities, maintenance, commuting, childcare, and savings goals don’t show up in DTI but matter for comfort.
- Try scenarios: Adjust the rate, term, taxes, and insurance to see how the loan and home price shift.
Informational only — not financial advice. Lender criteria vary and may include credit, reserves, and LTV checks.
5 Fun Facts about Loan Affordability
Taxes can be the “hidden” third
In some regions, property tax alone can swallow 20–35% of the allowed housing payment—bigger than insurance and often bigger than PMI.
Location swing
PMI isn’t forever
Hit ~78% loan-to-value and many loans auto-cancel PMI; nudging your down payment by a few percent can erase a monthly line item entirely.
Drop-off win
Term tweaks shift the ceiling
Shorter terms crush total interest but also shrink the max loan this calculator will show. A 20-year term can cut the principal ceiling by ~10–20% vs 30-year, same payment cap.
Trade-off
DTI caps aren’t universal
Some programs bend front/back caps (e.g., 28/36 → 31/43 or higher) for strong credit and reserves. Lowering other debts often buys more room than chasing a tiny rate drop.
Flexible rules