What Months of Supply Actually Tells You About Local Housing Conditions

How the Number Is Calculated

The math behind months of supply is straightforward. Take the total number of homes currently listed for sale in a given area, then divide by the average number of homes sold per month over a recent period — typically the past three to twelve months. The result tells you, in theory, how many months it would take to clear the existing inventory at the current sales pace.

For example, if a market has 600 active listings and averages 200 sales per month, that produces three months of supply — a figure that strongly favors sellers. If that same market had 1,400 listings with the same sales pace, it would show seven months of supply, leaning toward buyers.

For a broader look at how this figure fits alongside other housing data points, see our guide to reading a housing market report without getting lost in the numbers.

What the Benchmarks Actually Mean

The six-month benchmark is a rule of thumb, not a law. It emerged from historical patterns suggesting that at six months of supply, neither buyers nor sellers hold a decisive structural advantage — prices tend to be relatively stable and negotiation is more mutual.

• Under 4 months: A strong seller's market. Homes often sell quickly, sometimes above list price, with limited room to negotiate on repairs or contingencies.
• 4–6 months: A moderately competitive market. Conditions are more balanced, though still often tilted slightly toward sellers in most US metros.
• 6 months: The traditional balanced-market threshold. Prices tend to be stable and buyers have meaningful leverage.
• Over 6 months: A buyer's market. Sellers may need to reduce prices or offer concessions to attract offers. Homes sit on the market longer.

It is worth noting that these ranges are not rigid. A market at 5.5 months can feel like a seller's market in one region and a buyer's market in another, depending on local norms and price segments.

Why Local Context Is Everything

National months of supply figures make headlines, but they are averages built from thousands of individual local markets — and averages can mask enormous variation. A national reading of five months might reflect a mix of markets with two months and markets with nine months, none of which describes your specific neighborhood.

Price tiers add another layer. Even within a single city, the months of supply for entry-level homes might be two months while luxury properties sit at eleven months. Treating a citywide number as representative of every segment can lead buyers and sellers to misread their actual position.

This is why local data almost always tells a different story than national headlines. When evaluating months of supply, request figures from a local agent or MLS that are specific to your target zip code and price range.

How to Use This Metric When Making a Housing Decision

Months of supply is most useful when read as part of a pattern over time rather than as a single snapshot. A market moving from eight months to five months over six months signals tightening conditions — sellers are gaining leverage even if the absolute number still looks buyer-friendly. The direction of change matters as much as the level.

Pair it with related indicators for a fuller picture. Days on market tells you how quickly homes are actually selling. The list-to-sale price ratio shows whether sellers are getting their asking price. Understanding how overall inventory levels move helps explain why months of supply shifts in the first place.

Also be aware of seasonal noise. Inventory typically rises in spring and falls in winter across most US markets, which can cause months of supply to fluctuate without reflecting a structural shift in demand. Seasonality shapes listing and sales patterns throughout the year and should be factored into any month-to-month comparison.

For those trying to time a major housing decision, months of supply is one of several indicators worth monitoring together rather than relying on any single data point.