Article
How to choose comparable homes for an assessment review
Updated September 22, 2026 · 3 min read
Almost every assessment review comes down to one question: is your home assessed consistently with homes like it? Choosing the right homes to compare with is most of the work. Here's how to do it well, and how we do it.
What "comparable" means
A comparable property is one an assessor would accept as similar to yours in the ways that drive value. In practice that means:
- Location. The same community or neighbourhood. Value varies street by street, but a community is a fair starting point.
- Type. Detached with detached, townhouse with townhouse, condo unit with condo unit.
- Age. Homes built around the same time were usually built to similar standards.
- Size. Similar living area and similar lot size.
Our check applies those rules the same way for every property. Similar homes means: same community, same structure type, built within 10 years of yours, living area within ±15%, lot size within ±25%, and at least 8 of them.
Why a group, not one house
One comparable is an anecdote. A group is evidence. If you pick the one house on your street with the smallest assessment, the assessor will point out why it's different, and they'll usually be right. A group of similar homes, compared through the median value per square foot, is much harder to argue with. The median is the middle value, so one odd house doesn't skew it.
If fewer than 8 homes match, we widen the criteria one step at a time and show you which step we used. A comparison built from a wider step is looser, and your result says so.
Compare per square foot
Two homes of different sizes can't be compared on total value. Divide each assessed value by its size. Living area is the usual measure, and lot size when living area isn't published. Then compare yours with the median of the group.
Example (illustrative round numbers)
Your home: $600,000 and 2,000 sq ft, which is $300 per sq ft. Eight similar homes range from $265 to $295 per sq ft, with a median of $280. Your value per square foot is about 7% above the median. Whether that gap is worth pursuing depends on the tax it represents and on the risks described below.
Traps that weaken a case
- Cherry-picking. Choosing only the smallest values. Assessors see this constantly.
- Mixing types. A bungalow isn't comparable with a two-storey of the same size.
- Ignoring differences you know about. If your home has a finished basement and the comparables don't, say so. It may explain the gap.
- Listing prices. An asking price isn't evidence of value. Sales and assessed values are.
- Forgetting the risk. If your home turns out to be assessed below similar homes, a review can raise it. If a review could plausibly raise your assessment, we tell you and don't recommend filing.
Special cases
- New Ontario subdivisions. Compare within the subdivision, where homes share a builder and era. For new Ontario homes, we compare with homes in the same subdivision built within 2 years of yours.
- Calgary. Calgary's open data doesn't include living area, so for Calgary houses the first comparison uses value per square foot of lot, and we confirm living area from your notice before building a case.
- Condos. Compare units in the same building or similar buildings, of similar size, floor and view where that information is available.
Presenting comparables to an assessor
Keep it to one page. List the homes with address, type, year built, size, assessed value and value per square foot. Show the median, show yours, and state the value you believe is consistent. Attach proof of any factual errors separately. A clear table invites a clear answer.
Our result page shows the most similar homes we used, with their public values, so you can see our work and bring it to the assessor yourself if you like. You don't need us: you can contact your assessor or file a complaint yourself.
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