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Brian McKay

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MBR Housing Affordability Index: Methodology

The MBR-HAI is the first housing affordability index updated daily using live mortgage rates from over 8,888 verified rate quotes across 1,750 U.S. banks and credit unions. While the NAR Housing Affordability Index publishes once per month using estimated rates, the MBR-HAI reflects what lenders are actually offering today, giving buyers, journalists, and researchers a real-time read on affordability the moment rates move.

Live Score

100.7

Near National Average

National MBR-HAI • May 6, 2026

-0 vs. prior day

100: National average baseline

Above 100: More affordable than average

Below 100: Less affordable than average

Rate component based on 6.306% 30-year national average • May 6, 2026

What the MBR-HAI Measures

The MBR Housing Affordability Index answers one question: how affordable is homeownership in this market, relative to the national average? A score of 100 equals the national baseline. A score of 80 means homeownership is moderately less affordable than average. A score of 120 means it is significantly more affordable.

Unlike single-metric indexes that only compare income to mortgage payments, the MBR-HAI incorporates the full cost of ownership: property taxes, total housing costs, and what share of households are actually experiencing cost burden, alongside market supply signals like homeownership and vacancy rates.

The index is anchored to a fixed national reference baseline computed at the long-run reference rate of 6.5%. This means the index moves when rates change, allowing daily tracking of how affordability shifts as the Federal Reserve acts, bond markets move, or lender competition changes.

Score Interpretation

120+	Highly affordable, well above national average
110–119	More affordable than the U.S. average
90–109	Near the national average
70–89	Moderately less affordable
50–69	Significantly less affordable
Below 50	Among the least affordable markets in the U.S.

MBR-HAI vs. NAR HAI

MBR-HAI

10 components
Daily updates
Actual verified bank rates
National + 51 states
Taxes & cost burden included

NAR HAI

1 component
Monthly updates
Estimated rates
National + metros only
Payment-to-income only

How the MBR-HAI Is Calculated

The MBR-HAI uses a qualifying income method as its primary rate component, the same approach used across standard housing affordability research, then blends in eight additional Census-derived components. The 28% qualifying income threshold aligns with conventional mortgage underwriting standards. This gives the index meaningful rate sensitivity while incorporating far more dimensions of affordability than single-metric indexes.

Component Weights

Rate & qualifying income burden carries the most weight because it is the component that changes daily and most directly determines whether a buyer can qualify for a loan.

The Core Formula

Step 1: Local qualifying income ratio

                    Monthly P&I = loan_amount × rate_formula

                    Qualifying_Income = (Monthly_P&I / 0.28) × 12

                    Local_Ratio = Local_Income / Qualifying_Income
                    Step 2: Score relative to national reference

                    Component_Score = 100 × (Local_Ratio / National_Ratio_at_Ref_Rate)
                    Step 3: Weighted composite

                    MBR-HAI = Σ(Component_Score × Weight)

Jumbo market adjustment: When 80% LTV of the local median home value exceeds the FHFA conforming loan limit, the effective rate is increased by 0.25% to reflect jumbo loan pricing, and the conforming access component is penalized by 10 points. This captures the invisible affordability barrier that forces buyers into stricter qualifying requirements.

All 9 Components

Component	Category	What It Measures	Data Source	Update Frequency	Weight
Qualifying income burden	Rate & Income	Monthly P&I vs. qualifying income threshold relative to national ratio at reference rate	MBR live rate database + U.S. Census Bureau median household income	Daily	25%
Rate spread	Rate & Income	Current live rate vs. long-run reference rate of 6.5%	MonitorBankRates.com, 8,888 daily verified rate quotes	Daily	10%
Price-to-income ratio	Home Value	Median home value divided by median household income, vs. national PTI	U.S. Census Bureau, median home values and household income	Annual	15%
Conforming limit access	Home Value	Whether 80% LTV of median home exceeds FHFA conforming limit (jumbo territory)	Federal Housing Finance Agency conforming loan limits	Annual	10%
Median owner costs	True Cost	Selected monthly owner costs (mortgage, taxes, insurance, utilities) as % of income	U.S. Census Bureau, selected monthly owner costs	Annual	10%
Property tax burden	True Cost	Median annual property taxes (mortgage holders) vs. national median	U.S. Census Bureau, median real estate taxes paid	Annual	10%
Homeownership rate	Market Conditions	Owner-occupancy rate as a signal of market accessibility	U.S. Census Bureau Current Population Survey	Quarterly	5%
Homeowner vacancy rate	Market Conditions	Available housing supply signal: low vacancy pushes prices up	U.S. Census Bureau Current Population Survey	Quarterly	5%
Owner cost burden	Reality Check	% of mortgage holders spending 30%+ of income on housing (federal cost-burden threshold)	U.S. Census Bureau, owner housing cost burden	Annual	5%
Renter cost burden	Reality Check	% of renters spending 30%+ of income on rent, measures full housing ecosystem stress	U.S. Census Bureau, renter housing cost burden	Annual	5%

Why Daily Rates Change Everything

Every other housing affordability index in the United States uses estimated or lagged mortgage rates. The NAR publishes its index once per month, using Freddie Mac's weekly Primary Mortgage Market Survey as its rate input. As a result, the published index can be 4–6 weeks behind actual market conditions at any given time.

MonitorBankRates aggregates over 8,888 verified mortgage rate quotes from 1,750 lenders every night. These are not estimated rates, not rate sheet averages, and not teaser rates. They are actual quotes verified directly from official institution websites by our proprietary aggregation systems and dedicated team of rate updaters. When the Federal Reserve acts, when bond markets move, or when lender competition intensifies, our database reflects it by the next morning, and so does the MBR-HAI.

A 0.25% change in the national 30-year average shifts the MBR-HAI by approximately 0.8–1.0 index points nationally. In markets where affordability is already near the threshold (Nashville or Phoenix, for example), that shift can move a market from “near national average” to “moderately less affordable” in a single week.

Rate Sensitivity by Market Type

Market@ 5.0%@ 6.5%@ 8.0%

Kansas City, MO 112.6 105.9 101

Nashville, TN 94.9 90.5 87.1

Chicago, IL 89.6 84.3 80.2

Boston, MA 74 67.6 65

Miami, FL 75.2 68 65.9

Los Angeles, CA 63.6 55.5 53.8

More affordable markets show greater index movement when rates change because the mortgage payment represents a larger share of what income can support. In high-cost markets, home prices and income gaps dominate the score regardless of rate level.

Data Sources & Update Schedule

Rate Data · Updates Daily

MonitorBankRates Live Rate Database

30-year fixed mortgage rates computed nightly from 8,888 verified rate quotes across 1,750 FDIC-insured banks and NCUA-chartered credit unions reporting nationally. Every rate is sourced directly from official institution websites, not from rate sheets, published averages, or third-party estimates. Each quote is time-stamped and institution-attributed for full transparency.

Housing & Income Data · Updates Annually

U.S. Census Bureau, American Community Survey

Median home values, median household income, selected monthly owner costs, property taxes, and owner and renter cost burden percentages. National, state, and local data is incorporated and refreshed annually as new estimates become available.

Market Conditions · Updates Quarterly

U.S. Census Bureau, Current Population Survey

National and state homeownership rates and homeowner vacancy rates. Updated quarterly as new survey data becomes available.

Loan Limits · Updates Annually

Federal Housing Finance Agency

Conforming loan limits used to determine whether median home buyers in a given market enter jumbo loan territory, which triggers stricter qualifying requirements and a rate premium. Refreshed annually as new limits are published.

Data Downloads

Download MBR-HAI Historical Data

Daily national & state scores in CSV and JSON, updated every morning.

Download Data →

Frequently Asked Questions

What is the MBR Housing Affordability Index?

The MBR Housing Affordability Index (MBR-HAI) is a composite score measuring how affordable homeownership is in a given market relative to the national average. A score of 100 equals the national average. Scores above 100 indicate markets that are more affordable than average; scores below 100 indicate less affordable markets. The index is updated daily using live mortgage rates computed from verified rate quotes across lenders reporting nationally to MonitorBankRates.com.

How is the MBR-HAI calculated?

The MBR-HAI uses a weighted composite of 9 data components across 5 categories: (1) Qualifying Income Burden at 35% weight, using the qualifying income formula comparing local mortgage payments to local income; (2) Home Value and Price Barrier at 25%, including the price-to-income ratio and conforming loan limit access; (3) True Ownership Cost at 20%, including median owner costs and property taxes; (4) Market Conditions at 10%, including homeownership and vacancy rates; and (5) Cost Burden Reality at 10%, including owner and renter cost burden percentages. The rate component updates daily; Census-derived components update annually.

How is the MBR-HAI different from the NAR Housing Affordability Index?

The NAR HAI uses a single formula: median family income divided by the qualifying income needed for a median-priced home. It updates monthly and covers national and metro-level data only. The MBR-HAI uses 9 components across 5 categories, incorporates actual mortgage rates aggregated daily from over financial institutions rather than estimated rates, adds property taxes, total owner costs, and cost burden data that NAR omits, and updates every day rather than once per month. The result is a more comprehensive and more timely measure of affordability.

What does a score of 100 mean?

A score of 100 means the market has the same affordability profile as the national average. Scores above 100 mean the market is more affordable than average; scores below 100 mean it is less affordable. For example, a score of 80 means the market is moderately less affordable than the national baseline, while a score of 120 means it is significantly more affordable.

How often does the MBR-HAI update?

The rate-dependent component of the MBR-HAI updates every night at 11pm using 30-year fixed mortgage rate averages computed from verified rate quotes across lenders reporting nationally to MonitorBankRates.com. The full index score updates daily. U.S. Census Bureau components update annually as new estimates are released. Market condition components update quarterly.

Can I download the MBR-HAI historical data?

Yes. Daily MBR-HAI scores for the national average and all 51 states are available for download as a CSV file from the MBR Housing Affordability Index page. The file includes the index score, the 30-year rate used, and the date for each observation.

Why does the index include property taxes and cost burden data?

Most affordability indexes, including the NAR HAI, measure only the mortgage payment relative to income. But homeowners also pay property taxes, insurance, and utilities. Including median owner costs and property taxes produces a more accurate picture of what housing actually costs. The cost burden percentages (the share of households spending 30% or more of income on housing) serve as a reality check, validating the index against observed behavior rather than just theoretical calculations.

Press & Research Inquiries

Journalists and researchers are welcome to cite the MBR-HAI. Please link to this methodology page and credit data as “MBR Housing Affordability Index, MonitorBankRates.com.”

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Explore the MBR-HAI

National MBR-HAI Score

Today's national index score, historical chart, and state rankings.

Current Mortgage Rates

Compare live 30-year and 15-year rates from banks and credit unions nationwide.

Mortgage Rate Trends

Historical rate trend charts updated daily from 1,750+ monitored lenders.