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Home/US Finance/Home Affordability Calculator (28/36 Rule)

¿Qué es la Calculadora de Asequibilidad de Vivienda?

La Calculadora de Asequibilidad de Vivienda determina el precio máximo de casa que usted puede comprar según sus ingresos, deudas existentes, pago inicial disponible y tasas de interés actuales. Aplica las reglas del 28/36 (28% del ingreso bruto para vivienda, 36% para todas las deudas) y la regla del 'salario neto del 30%' usada por planificadores financieros conservadores.

Home Affordability Calculator (28/36 Rule)

How much house can you afford? Uses the standard 28/36 front-end and back-end debt-to-income ratios.

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← US Finance
Estimates only. Not tax, legal, or financial advice. Verify with your CPA, advisor, or the relevant IRS / SSA / CMS source for decisions with material impact.

TLDR

The 28/36 rule says PITI (principal, interest, taxes, insurance) should be at most 28% of gross monthly income, and total debt (PITI + car loans + credit cards + student loans) at most 36%. Lenders may approve higher; do not stretch.

Cómo usar this calculator

  1. Enter your inputs. Each field is labeled with its unit (dollars, percent, age, etc.).
  2. Read the result instantly. Numbers update as you type - no submit button.
  3. Adjust to test sensitivity. Change one input at a time to see what moves the result most.
  4. Cross-check the formula in the section below. Calculator math should match the published formula.
  5. Copy or screenshot the result for later. The site does not save anything; close the tab and inputs are gone.

Acerca de esta herramienta + formula

This calculator uses real 2025-26 IRS, SSA, and CMS published values. The math runs entirely in your browser - nothing is sent to a server. The underlying formula is:

front_end = monthly_income * 0.28
back_end = monthly_income * 0.36 - other_debt
max_PITI = min(front_end, back_end)
max_price (solve from PITI = (price - down) * factor + price * tax/12 + ins + hoa)

Sources: IRS contribution limits, SSA reduction factors, CMS Medicare premium tables, US Treasury auction yields, HHS Federal Poverty Guidelines. Numbers are refreshed annually as new figures publish.

Escenarios del mundo real where this calculator helps

First-time buyer planning

Run before you start house-hunting. Lock in a max price you will not exceed regardless of what the lender approves.

Bidding war discipline

Hot market, multiple offers. Knowing your hard ceiling stops you from over-bidding by €20K just because the seller demands more.

Refinance vs move

Compare what you can afford today (current rates) vs your existing mortgage. Often shows that the affordable house at 7% costs the same monthly as the dream house at 3% you bought in 2021.

Move-up planning

Selling current home + moving up. Use the equity from the sale as the new down payment input.

What this tool does

  • Applies the 28% front-end ratio (PITI vs gross income).
  • Applies the 36% back-end ratio (PITI + other debt vs gross income).
  • Solves for max home price given the binding constraint.
  • Includes principal, interest, property tax, insurance, and HOA in PITI.
  • Reports a conservative (25%) and aggressive (back-end ceiling) range.

What it does NOT handle

  • Doesn't include PMI (most lenders charge until LTV reaches 80%, around €50-€200 / mo).
  • Doesn't compute closing costs (typically 2-5% of price).
  • Doesn't model points / origination fees.
  • Doesn't apply jumbo loan limits or FHA / VA rules.
  • Doesn't predict your actual approval - lenders use AUS scoring with credit + asset checks.

Errores comunes and pitfalls

  • Using gross income instead of net. The 28/36 rule uses gross (pre-tax). Make sure you can actually live on what is left after taxes + retirement + savings.
  • Forgetting the property tax can swing wildly by location. Texas often 2.5%, Hawaii 0.3%. Always look up the actual county rate.
  • Skipping HOA. HOAs in CA condos can easily hit €700 / mo - that is €700 less of mortgage you can afford.
  • Using the lender's max approval as your target. Lenders approve up to 43-50% DTI. That stretches you thin if anything goes wrong.
  • Ignoring maintenance reserves. Plan 1% of home value per year for repairs.

Preguntas frecuentes

What is the 28/36 rule?

Industry guideline: housing payment (PITI) should not exceed 28% of gross monthly income, and total debt should not exceed 36%. Used by Freddie Mac and most conventional lenders as a benchmark.

What is PITI?

Principal + Interest + property Tax + insurance. The full monthly cost of owning a home, used in DTI calculations.

What is DTI?

Debt-to-Income ratio. Front-end DTI = PITI / gross income. Back-end DTI = (PITI + all other debt) / gross income.

Will the lender approve more?

Often yes, up to 43-50% back-end DTI for conventional, sometimes higher for FHA. Approval does not equal affordability - the 28/36 rule is the sustainable target.

What about PMI?

Private Mortgage Insurance: required on conventional loans with down payment under 20%. Roughly 0.3-1.5% of loan annually, removed once you reach 80% LTV. This calculator does not include it - add ~€100-200 / mo if applicable.

How much down payment do I need?

Conventional: 5-20%. FHA: 3.5%. VA / USDA: 0%. Twenty percent down avoids PMI but is not required for approval.

Are property taxes always 1.1%?

No. National median is around 1.1%, but ranges from 0.3% (Hawaii) to 2.5% (Texas, NJ, IL). Look up the actual rate for your county.

Should I buy at the top of my range?

Generally no. Leaving 10-20% buffer below your max protects against rate hikes, job loss, repair surprises, and lifestyle changes. Buy at 80% of your DTI cap if possible.