4 Person Mortgage Calculator

Reviewed by: David Chen, CFA
David Chen is a Certified Financial Analyst with over 10 years of experience in multi-borrower mortgage analytics and household affordability modelling.

Use this 4 person mortgage calculator to combine four incomes, debts, and credit scores into one borrowing power estimate and monthly P&I payment—perfect for friends or family buying together.

4 Person Mortgage Calculator

Result will appear here
Not calculated yet.

4-Person Mortgage Formula

Monthly P&I: M = P × [ r(1+r)^n ] / [ (1+r)^n – 1 ]

DTI Check: (P&I + Debts) ÷ Gross Monthly Income ≤ 43%

Formula Sources: Fannie Mae | HUD

Variables

  • Combined Income: Gross annual income for all four borrowers.
  • Total Monthly Debts: Car loans, student loans, credit cards, etc.
  • Loan Amount: After down payment.
  • Interest Rate & Term: Applied to the single mortgage.

Related Calculators

What Is a 4 Person Mortgage Calculator?

It combines four incomes and debt obligations into one household borrowing profile. Lenders use the lowest median credit score and the sum of incomes, but only the debts of borrowers on the loan. This widget estimates maximum P&I and checks blended DTI.

How to Calculate 4-Person Mortgage (Example)

  1. Enter the home price (e.g., $800,000).
  2. Input total down-payment percentage (e.g., 10%).
  3. Set the term (e.g., 30 years) and interest rate (e.g., 6.5%).
  4. Add combined annual income for all four borrowers (e.g., $240,000).
  5. Input total monthly debts for everyone on the loan (e.g., $3,000).
  6. Click “Calculate” to see monthly P&I and blended DTI.

Frequently Asked Questions (FAQ)

Do all four borrowers need to be on the loan? Yes—lenders underwrite all signatories; non-borrower income is disregarded.

Which credit score is used? The lowest median score among the four borrowers.

Can we use FHA with four borrowers? Yes—FHA allows up to four co-borrowers; all must occupy the property.

Is the result guaranteed? No—lenders also consider reserves, employment history, and property type; use as a ball-park only.