My home could sell for $250,000 or $335,000. It all depends on whom you ask.

"What's my home worth?" is a question many Puget Sound-area homeowners are asking themselves these days: The median price of houses and condos combined in King, Snohomish, Pierce and Kitsap counties rose by 24 percent from 2000 to 2004, based on data from the Northwest Multiple Listing Service. In King County, median prices rose 10.7 percent in the first six months of 2005 alone.

If you plan to sell while the market's hot or want to apply for a home-equity loan, you need to know the value of your home. Even if you're just kicking the tires, as I've been recently, it's worth examining how different groups determine home values.

I don't plan to sell my house or borrow against it soon. But I'm curious because the 1918 Craftsman I bought last year in Delridge for $230,000 is my biggest asset — OK, my only real asset, aside from my laptop, a rusty Honda and a paltry IRA. Like many house-poor residents of the Puget Sound region, I wonder how much more of an asset it has become.

Three basic methods

There are three basic ways to find out your home's value: a comparative market analysis (CMA) provided by a real-estate agent who researches prices of houses similar to yours (known as "comps"); a professional appraisal determined using a CMA; or the annual tax assessment provided from your county assessor's office.

Data land

If you're curious about finding your home's potential market value, here are some resources to help get you started:

Appraisal Institute: www.appraisalinstitute.org lists credentialed appraisers by city.

Domania: www.domania.com offers a service called Home Price Check and reports on recent transactions in your area.

Electronic Appraiser: www.electronicappraiser.com charges for basic components of an appraisal, with reports costing $4.95 to $29.95.

HomeGain: HomeGain.com lets you order a free online comparative market analysis and allows you to search recent sales.

HouseValues: HouseValues.com lets you order a free online comparative market analysis, arrange for an agent to visit your home, and sign up for notifications of new listings in your area.

County assessor: County assessors determine home values using formulas in their counties.

Northwest Multiple Listing Service: www.nwrealestate.com shows active and pending listings in 15 Washington counties; research press releases to determine price appreciation and apply those appreciation rates to your home's most recent county assessment.

Each of these valuation methods relies on home-sales data collected by the Multiple Listing Service (MLS) and combines it with human observation and context, which is why price points can vary so dramatically.

The MLS makes current listings available to consumers online at www.nwrealestate.com. But if you're a real-estate professional, you can use MLS databases to dig around for historical sales data and details about properties in sophisticated ways that regular folks can't.

Generally speaking, an appraisal is the best way to get a sense of your home's value, said Glenn Crellin, the director of the Washington Center for Real Estate Research at Washington State University.

Appraisers calculate values used by banks and lenders in determining loan risk, Crellin said, so their figures are generally conservative and realistic.

However, Crellin said, that rule changes in a hot housing market in which prices are escalating rapidly.

"In the current environment of rapidly rising prices, a Realtor's CMA may be more accurate," he said.

Michael Essig, an appraiser with Investors Real Estate Group who compiled appraisal figures for my property, agreed. Agents have a better sense of what a house will sell for.

"We view things differently than agents do," Essig said, noting that appraisers pay careful attention to its structural condition. "We all use the same basic source — closed sales — but (the numbers) depend on how the data are used."

A tax assessment calculates a number for taxation purposes only, although agents use the same methodology.

But the differences became abundantly clear as I began to gather CMAs from agents and an appraiser.

Online analysis with real-estate portals

First, I went online to HouseValues (HouseValues.com and filled out long forms detailing information about my property. I knew most of the essentials — four bedrooms, two bathrooms, oil heat, 1918 construction — but the forms allow for subjective calls about some things: I had to rate the "condition" of my house on a scale of 1 to 10. (I picked 5.)

I also had to choose its square footage, which is challenging. My partially daylit basement is also only partially finished. The home was listed as having 2,080 square feet when I bought it, but county records say it has 1,490 finished square feet (acknowledging the utility portion of my basement as unfinished). I used 1,490 square feet.

Within days, I received an online market analysis from an agent, Gary Looney of Alpine Real Estate in Seattle, who got my name from HouseValues. Looney offered the most optimistic value: He said my asbestos-shingled abode would sell for $320,000 to $335,000.

I repeated the online process with HomeGain (HomeGain.com) and received an online market analysis from agent Lance Calvin of ZipRealty. He said my home would sell for $250,000 to $260,000, but noted that he said he found only two houses legitimately comparable — a small pool. He used other tools, such as a geographic search, to find more comps.

Both HomeGain and HouseValues recommend that online tire-kickers get a more formal — and ostensibly more accurate — CMA by having an agent visit their home.

Offline analysis with real-estate agents

So I had Looney come by to check out my place. He said my home's condition was somewhere between a 4 and 5 then walked through and studied it as if it were about to hit the market.

He liked the fir floors, big kitchen, the period details and the deck. But after seeing some of its humbler features — the semifinished basement with low ceilings and the aging siding — he lowered the range: $295,000 to $310,000. He also set a few conditions: I'd have to do more landscaping and complete a planned $2,500 electrical-system upgrade.

I asked my real-estate agent, Samantha Macintosh of Prudential Michael Smith Realtors in Bellevue, to provide a CMA. I told her that the only changes I'd made since she helped me buy it in 2004 were painting the interior, replacing vinyl flooring in the basement bathroom, and carpeting about 800 square feet of the basement to make it housemate-friendly.

Macintosh, who has worked with buyers in my neighborhood and stopped by my home a few times during the past year, came in with a range of $275,000 to $300,000. To fetch more, she said, I'd need to make major improvements, such as remodel the kitchen.

Assessor's analysis

County assessor's figures are calculated using sales data from the previous two years, said Stan Rowe, an assistant to King County Assessor Scott Noble. That means the assessment I received last month ($244,000) was calculated using sales data from 2003 and 2004.

The $244,000 is a basis for my taxes during 2006, my notice said. For an up-to-date market value, Rowe said I could take the rate of appreciation among King County houses from January 2005 to July 2005 (10.7 percent, based on MLS data) and apply that increase to my assessment. That bumps my home's worth to $270,108. It won't be as accurate as an agent's CMA, he said, but it's not a bad back-of-the-envelope method for gauging what a CMA might say.

Appraiser's analysis

Essig, the appraiser, explained that he looks at three components of a home — location, condition, and the scope and quality of improvements — to determine which homes are comparable.

Unlike the real-estate agents, Essig decided to eliminate my basement square footage and consider only my home's fully finished space, 930 square feet. The basement, while habitable, has low ceilings and exposed piping and ducts. You could live there, but it wouldn't be that nice.

Essig looked at comparable homes no bigger than 1,320 square feet. After driving by seven comparable homes, he said the price of my house might fall in the $258,000 to $263,000 range, based on the average price of all the comps. Later that day, though, he wrote and said that based on its condition, he'd bump the figure down to $255,000.

Different interpretations

Each person involved in this process handicapped my home differently when it was compared to seven comparable houses. Perception is what makes the figures fluctuate. The observer's experience counts too — the longer the agent or appraiser had been in the business, the more conservative the estimates.

The homeowner's perception also plays a role.

Earlier this year, I did some online research and ranked my home a "10" in quality. I got a report back saying it would be valued like a recent $379,000 sale two blocks away. Of course, my home is no "10," but if I were an optimistic consumer, I could deceive myself using online tools.

Among the people who did comps on my house, Essig, the appraiser, took the most cynical outlook: He looked at houses listed or sold for under $299,000 in calculating comparables, counted my square footage as my main floor's 930 square feet, and compared my place to houses no bigger than 1,320 square feet. He tried to compare my older home to those from a similar time period, but he said it was hard to find recent transactions among such houses in my area.

Macintosh, my real-estate agent, compared my house to those priced between $250,000 and $299,950. (She said she did look at higher-priced homes initially but ruled them out because their condition and finishes were of a higher quality than those in my house.) She considered my true square footage as 1,490 and ultimately compared my house to those ranging from 1,310 to 1,750 square feet — starting at the square-footage range where Essig left off. She reviewed homes built from 1918 to 1980.

Looney took my home's square footage as 1,490 (including the partially finished, partially daylit basement) and ultimately compared it to houses with 1,060 to 1,880 square feet, built between 1924 and 1980, and listed or sold from $220,000 to $382,500.

Calvin compared my house with two properties that sold within the past two months — one for $240,000 and $259,950 — and that had 1,410 to 1,640 square feet and larger lots of up to a quarter-acre (my grandfathered minilot is 0.11 acre).

He then did a search of houses that listed, sold or remain pending within a half-mile of my house over the past six months and noted that their median price was $249,910. A home visit, he said, would clarify things.

In the end, I'm not sure whose numbers I trust most, or why the range of values varied so much, but I'd like to believe a comment Looney made: "A home may be worth only $200,000, but not if someone is willing to pay $300,000 for it."

If I ever list my home, I'll hope the $300,000 "someone," not an appraiser, comes to the open house.

Jane Hodges: janehodges@hotmail.com