It's a seller's market -- at least temporarily -- for homes in the region priced between $150,000 and $400,000.

For homes $600,000 and up? Buyer's market all the way.

That's where things stood in May for the Baltimore metro area, based on a handy calculation that helps show the balance of power with a single number.

It's the "months of supply" -- the number of homes on the market divided by the number of homes sold. That answers this question: How long it would take to find buyers for all the listed properties at the pace things are selling?

Economists generally call six months a balanced market. The advantage shifts to buyers as the number rises and to sellers the farther below six months the supply falls.

One thing to remember about May and other late spring or early summer months is that this is when many homebuyers like to buy. That gives sellers a boost. (There are also lingering questions about when the foreclosure "shadow inventory" will hit the market, so -- to borrow a well-worn phrase from the financial industry -- past performance is no guarantee of future results.)

With that in mind, here's why some price ranges might feel way harder for buyers than those buyers might have expected:

For homes priced at $150,000 to $199,999 in the Baltimore metro area, the months' supply is 4.5.

For the $300,000s, it's 4.3.

And for the $200,000s, it's 4.1 -- lowest of any of the price ranges broken out by RealEstate Business Intelligence, the Rockville-based stats arm of the region's multiple-listing service.

The supply is under the magical six-month mark, though not so dramatically, for the $100,000 to $149,999 crowd and homes priced in the $400,000s. Both are at about 5.5.

Under $100,000 and the $500,000s are both at the other end of more-or-less balanced, hovering around 6.5.

That leaves the high-end homes, and there's a lot more competition for buyers in that category:

--More than 11 months' supply for homes priced in the $600,000 to $799,000 range

--About 18 months' supply for homes $800,000 to just under $1 million

--About 16 months' supply for homes priced at $1 million to nearly $2.5 million (25 sales in that range in May vs. 19 in the $800K-$1M, thus the slightly lower supply figure)

--About 19 months' supply for homes priced at $2.5 million to nearly $5 million

And for the $5 million-plus? The months' supply, in May at least, was infinite. (Eleven listings, no sales.) The pricier the home, the smaller the potential purchasing pool.

These figures can range a lot by neighborhood. If you're curious about months' supply near you, click on your ZIP code here ("ZIP Code: Select" near the top of the page). Then click on "Detailed Report" and do the math -- "active listings" divided by sales.

Here's 21042 in Ellicott City as an example. That figure: 3.2.

Got a housing news tip or experience to share? (Or just want to tell me something?) Email me at jhopkins@baltsun.com.