logic.codes

How Much House Can I Afford?

What home price fits my income under the 28/36 debt-to-income guideline?

Single calculationv1.0.0Verified 2026-11-01Runs in your browser

Spec sheet

dti_28_36 · v1.0.0
Method

Debt-to-income limits solved for price

  1. 01allowed housing = min(28 % × income, 36 % × income − debts) per month
  2. 02housing(P) = f·(P − down) + t·P/12 + insurance/12 + HOA, f = P&I per $ borrowed
  3. 03P = (allowed − ins/12 − HOA + f·down) / (f + t/12)
Limits — read before relying on it
  • A guideline, not a loan approval; lenders also weigh credit score, reserves and loan type (FHA/VA allow higher DTI).
  • Closing costs are not deducted from the down payment.
Sources

Worked example

computed by the same formula

$120k income, $500 debts, $60k down

Inputs
Gross annual income
120000
Other monthly debt payments
500
Down payment (cash)
60000
Mortgage rate
6.5 %
Loan term
30 years
Property tax rate (per year)
1.1 %
Insurance (per year)
1800
HOA (per month)
0
Front-end limit
28 %
Back-end limit
36 %
Result
Maximum home price
$418,556.81
Monthly housing budget
$2,800.00
Loan amount
$358,556.81
Limiting rule
Front-end (housing ≤ 28 % of income)
  1. 1. P&I per $ borrowed (npf.pmt) = 0.006
  2. 2. Front-end cap = 2,800
  3. 3. Back-end cap = 3,100

Questions

How is the how much house can i afford? calculated?

›

Debt-to-income limits solved for price. allowed housing = min(28 % × income, 36 % × income − debts) per month · housing(P) = f·(P − down) + t·P/12 + insurance/12 + HOA, f = P&I per $ borrowed · P = (allowed − ins/12 − HOA + f·down) / (f + t/12)

Example: $120k income, $500 debts, $60k down?

›

Maximum home price: $418,556.81; monthly housing budget: $2,800.00.

What does this calculator not cover?

›

A guideline, not a loan approval; lenders also weigh credit score, reserves and loan type (FHA/VA allow higher DTI). Closing costs are not deducted from the down payment.

Where do the numbers come from?

›

Sources: Conventional 28/36 debt-to-income guideline (lender rule of thumb); numpy-financial (BSD-3) — ported to TypeScript. The formula is versioned (dti_28_36 v1.0.0) and covered by automated tests.

Is my data stored?

›

No. The calculation runs in your browser and nothing is sent unless you choose to save a shareable link.

Also searched ashow much house can i afford · home affordability calculator · mortgage affordability · 28 36 rule · how much mortgage can i afford

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