Your tax bill is built on assessed value, a county’s own administrative number, not market value, what a buyer would actually pay today. Counties get from one to the other with a fixed assessment ratio and a multi-year reassessment cycle, and both mechanics tend to leave assessed value trailing market value when land prices are rising.
What’s the Difference Between Assessed Value and Market Value?
Market value and assessed value answer two different questions, and confusing them is the single most common reason a landowner is surprised by either a tax bill or a sale price. Market value is what a specific parcel would actually sell for; assessed value is a number a government office calculates to divide up the local tax burden.
Federal bank regulators define market value in the appraisal rules that govern mortgage lending. Under 12 CFR 34.42, which the Office of the Comptroller of the Currency uses to regulate real estate appraisals for national banks, market value means “the most probable price which a property should bring in a competitive and open market under all conditions requisite to a fair sale,” with both buyer and seller acting knowledgeably and under no unusual pressure to close. That’s an opinion about a specific parcel on a specific date, built from an appraiser’s analysis of recent comparable sales.
Assessed value starts from a different place entirely. A county assessor or auditor estimates a value for every parcel in the jurisdiction using mass appraisal, then applies a legal formula, usually a fixed percentage called an assessment ratio, to arrive at the number that actually gets taxed. Nothing in that process asks what a willing buyer would pay for your specific parcel this month; it asks what the countywide formula produces for a parcel like yours as of the last time the county looked.
How Does a County Turn a Value Estimate Into an Assessed Value?
A county multiplies its own estimate of a parcel’s value by a fixed assessment ratio set by state law, and that ratio, not the county’s underlying value estimate, is usually why your assessed value looks so much smaller than what the land would sell for. States set this ratio differently, and it can vary by the type of property within the same state.
Mississippi assesses real property by class. According to the Mississippi Constitution, Article 4, Section 112, Class I property, meaning single-family owner-occupied homes, is assessed at 10 percent of true value, while Class II property, which covers agricultural, rental, business, and most vacant land, is assessed at 15 percent. Mississippi State University Extension Service walks through the resulting math: a property assessed at $15,000 and taxed at a rate of 50 mills owes $750 in property tax, since the mill rate is applied to the assessed value, not the true value, of the parcel.
Ohio takes a different approach and applies one flat ratio to all real property instead of splitting it by class. According to the Allen County Auditor’s Office, “the assessed value of real estate is 35% of the property’s estimated market value” statewide, so a parcel the county appraises at $100,000 carries a $35,000 assessed value before any mill rate is applied.
Lining the two states up side by side on the same hypothetical parcel shows how differently states set this ratio:
| State | Applicable Ratio | On a $200,000 Estimated Value |
|---|---|---|
| Mississippi, Class II (most vacant land) | 15% | $30,000 assessed value |
| Mississippi, Class I (owner-occupied home) | 10% | $20,000 assessed value |
| Ohio, all real property | 35% | $70,000 assessed value |
A $200,000 parcel of Mississippi vacant land classified as Class II carries a $30,000 assessed value under that 15 percent ratio, according to Mississippi State University Extension, while the identical estimated value on an Ohio parcel computes to $70,000 under the county’s 35 percent rule, according to the Allen County Auditor’s Office. Neither number is “wrong” and neither is the market value; each is simply the output of that state’s ratio applied to the county’s own value estimate.
Why Don’t Counties Reassess Land Every Year?
Most counties don’t reassess every parcel annually because state law puts them on a multi-year cycle instead, alternating between a full physical reappraisal and a lighter statistical update in the years between. That schedule, not market activity, is what actually triggers a new assessed value.
Ohio law is explicit about the cadence. According to the Geauga County Auditor’s Office, “the State of Ohio mandates the County, ORC 5715.33 and 5715.34, to do a general reappraisal every six years and a triennial update during the third year after the general reappraisal.” During the sexennial reappraisal, appraisers physically examine construction quality, age, and condition alongside recent comparable sales. During the triennial update three years later, there’s no physical inspection; the county instead studies “the relationship of value to sales prices by taxing district” and adjusts values from that analysis.
The Lake County, Ohio Auditor’s office shows what that looks like on a real timeline: “the last revaluation was effective for the tax year 2021 and the next update will be completed for tax year 2024 which is payable in 2025.” That triennial update is built from “a study and analysis of sales that have taken place in the past three years,” meaning the value stamped on a 2024 tax bill is drawn from sales stretching back toward 2021, not from whatever the market was doing at the moment the bill went out.
Why Does Assessed Value Usually Lag Market Value in a Rising Market?
Assessed value tends to lag market value when prices are climbing because both mechanics described above point the same direction: a fixed ratio applies a discount to a value estimate that is, by design, already based on older sales data. Neither mechanic is designed to track a rising market in real time.
The ratio itself doesn’t cause the lag; it just scales the number down the way the Mississippi and Ohio ratios described above do. The lag comes from timing. A reappraisal or update sets a value using sales data collected before the assessment date, then that value typically stays fixed until the next reappraisal or update cycle, which in a state like Ohio can be up to three years later. If land in the area appreciates every year in between, the assessed value is chasing a number that has already moved on before the county even finishes calculating it. By the time a jurisdiction’s next cycle catches up and posts a higher assessed value, prices have often climbed further still, so the gap between the tax roll and the actual market rarely closes completely; it just resets a little smaller and starts widening again. The reverse can happen in a falling market, where a parcel’s assessed value can sit above what it would currently sell for until the next reappraisal catches the decline, which is one reason it’s worth checking your own county’s cycle rather than assuming your bill reflects today’s conditions either way.
Does the Gap Between Assessed and Market Value Matter If You’re Selling Land?
The gap matters because a county’s assessed value was never built to price a sale, and using it that way in either direction, as a floor or a ceiling, will usually mislead you. Buyers, appraisers, and lenders price land off comparable sales and site-specific conditions, not off a tax roll number calculated under a different formula on a different schedule.
A single-county example of that comparable-sales process is worth reading if you want the mechanics: how Maricopa County, Arizona values vacant desert land walks through a mass appraisal system built almost entirely around sales comparison rather than the assessment ratios discussed here, since Arizona structures its own property classes differently than Mississippi or Ohio. And the gap between an appraiser’s documented opinion of value and what a specific buyer will actually pay is its own separate question, covered in why a cash offer can beat an appraisal; a comparable sale analysis and an assessment-ratio calculation are simply answering different questions, using different inputs, on different clocks.
That’s also true if you’re deciding whether to sell rather than hold. A company like AMM Land Sales, which makes cash offers on vacant land directly to owners, prices a parcel off recent comparable sales and site conditions rather than off the county’s assessed value, the same way a listing agent or a mortgage appraiser would. If your county’s assessed value has stayed flat for a few years while sales in your area moved, that’s a sign the county simply hasn’t run its next reappraisal or update yet, not a signal about what the land would sell for today.
How Do You Find Your Own County’s Ratio and Reappraisal Schedule?
You find your county’s assessment ratio and reappraisal cycle on the assessor’s or auditor’s own website, which is required to publish both since they’re set by state law rather than left to the county’s discretion. Start there before assuming your bill reflects current conditions in either direction.
Look specifically for three things: the assessment ratio applied to your property’s class or type, the date of the county’s last full reappraisal, and the date of its next scheduled reappraisal or update. Most assessor sites publish a countywide schedule similar to Ohio’s, and many will also show the specific sales data or valuation date used for your parcel’s current assessed value. If you’re weighing whether to sell, that assessed value is a reasonable starting point for understanding your tax exposure, but it’s not a substitute for current comparable sales for figuring out what the land is actually worth.
| What to look up | Where it typically lives | Why it matters |
|---|---|---|
| Assessment ratio for your property class | State constitution, statute, or administrative code cited on the assessor’s site | Tells you how much the assessed value is discounted from the county’s own value estimate |
| Date of last reappraisal or update | County assessor/auditor’s reappraisal or valuation page | Tells you how old the sales data behind your current assessed value actually is |
| Date of next scheduled reappraisal or update | Same source, often published years in advance | Tells you when the assessed value is next likely to move, and in which direction |
If you own vacant land in Ohio, Mississippi, or any other state and you’re trying to figure out what the parcel is actually worth rather than just what it’s taxed on, a current set of comparable sales will tell you far more than your assessed value. That’s also true if you’d rather skip the market entirely and get a direct cash offer on raw acreage instead of waiting on the next reappraisal cycle to catch up.