How to Calculate Median Family Income

How to Calculate Median Family Income. A variety of government subsidized housing programs, use Median Family Income (MFI) determine eligibility for rental assistance and home ownership programs including Section 8. Median Family Income limits for every county or Metropolitan Statistical Area (MSA) use data based off of the most recent Census report released by the U.S. Department of Housing and Urban Development (HUD).

Step 1

Check the area definitions for that state. Area definitions are in a separate document that accompanies MFI data. If the county needed is not listed, it's most likely identified within an MSA.

Step 2

Access MFI data by state then locate the given county or MSA which is a county equivalent. The figure stated is the MFI (pre-taxes) for a four person family. The numbers listed for families with one through eight people are percentages of the MFI for that number of people in the family or household.

Step 3

Determine the number of person family when calculating MFI. Use the MFI listed for a four person family as the base figure (100 percent).

Step 4

Adjust from the base figure less 10 percent for each decreasing number person family under four people who reside in the household. For families of five and greater, increase from the base figure by 8 percent.


When applying for Section 8 housing assistance, you must meet the low-income or low-income standards given for that number of person family in the specific county.


Many states require 6 months residency before you can qualify for housing assistance. Check your specific state for rules that govern assistance programs.

Things You'll Need

  • Fiscal year MFI data

  • Calculator