Why It Matters
Here's what you need to know: multiply your property's assessed value by the millage rate and divide by 1,000 to get the annual tax bill. A property assessed at $200,000 with a 25-mill rate owes $5,000 per year. That fixed cost directly reduces your net operating income and shapes whether a deal pencils out.
At a Glance
- What it is: The property tax rate expressed per $1,000 of assessed value — 1 mill = $1 per $1,000
- The formula: Property Tax = (Assessed Value ÷ 1,000) × Millage Rate
- Who sets it: Multiple taxing bodies — county, city, school district, and special districts — each add mills that stack into a total rate
- Why it matters: Property taxes are a fixed operating expense; a 10-mill difference on a $400,000 property is $4,000 per year
- Where to find it: County property appraiser or tax assessor website, broken down by taxing authority
Property Tax = (Assessed Value ÷ 1,000) × Millage Rate
How It Works
The mill is the unit. One mill equals $1 of tax per $1,000 of assessed value — equivalently, 0.1% of assessed value. A 30-mill total rate means $30 in tax for every $1,000 of assessed value. On a $300,000 assessed property, that is $9,000 per year.
Assessed value is not market value. Most jurisdictions assess properties at a fraction of market value using an assessment ratio. A property worth $350,000 in a county with an 80% assessment ratio carries an assessed value of $280,000. The millage rate applies to that $280,000 figure, not the market price. When comparing markets, check both the millage rate and the assessment ratio — a low mill rate in a jurisdiction that assesses at 100% can cost more than a high mill rate where properties are assessed at 60%.
Multiple taxing bodies stack their rates. A single property rarely answers to one taxing authority. A typical bill might include 14 mills county, 9 mills city, 21 mills school district, and 3 mills special district — totaling 47 mills. Each body sets its rate independently, and each can change annually. The rate on the tax bill is always the combined total.
Millage rates reset each year. Governments adjust rates when budgets change. Even if your assessed value stays flat, a 2-mill increase from the school district raises your bill. For hold-period projections, assume modest annual increases rather than a locked rate.
Homestead exemptions do not apply to rentals. Many states reduce assessed value for owner-occupants — Florida's homestead exemption caps assessment increases at 3% per year and deducts up to $50,000 from taxable value. Investment properties typically do not qualify. When you buy a previously owner-occupied property, expect the tax bill to rise at the next assessment cycle.
Real-World Example
Marcus is comparing two duplexes: one in Dayton, Ohio priced at $180,000 and one in Memphis, Tennessee priced at $195,000. Both rent for about $1,800/month combined.
He pulls the tax records. The Dayton property sits in a district with a combined 72-mill rate applied to 35% of market value — assessed at $63,000, that produces a $4,536 annual tax bill. The Memphis property has a 3.19% effective rate applied to appraised value, coming to about $6,220 per year.
That $1,684 annual gap — roughly $140/month — closes most of the cash flow difference between the two deals. Marcus factors both the millage rate and the assessment ratio into his projections before making an offer, rather than relying on listing data that often lags by a year.
Pros & Cons
- Gives investors a precise, apples-to-apples measure for comparing property tax burdens across markets with different assessment practices
- Simple math once you have the assessed value and total mill count — no specialized software required
- Publicly available on county assessor websites, so it is easy to verify before making an offer
- Exposes hidden cost differences between similar deals in adjacent jurisdictions
- Requires knowing the assessment ratio to translate market value into tax cost — the mill count alone is not enough
- Rates change annually, so projections made at purchase can drift over a two- or three-year hold
- Multiple overlapping taxing bodies make the true rate harder to find than a single published number implies
- Assessment caps that benefit current owners can disappear after a sale, creating a tax increase the pro forma did not anticipate
Watch Out
- Tax reassessment after purchase: In many states, a sale triggers reassessment to the purchase price. If the previous owner held the property under a low assessed value for years, your first full tax year can bring a significant increase. Check whether the jurisdiction reassesses on sale before finalizing your numbers.
- School district boundaries: Two properties one block apart can sit in different school districts with mill rate differences of 10 or more. Always confirm the exact parcel address and school district before relying on a neighborhood-level tax estimate.
- Special assessment districts: Certain areas carry additional mill levies for fire, water, drainage, or community development districts. These are often omitted from summary tax rate tables but show up on the actual bill. Pull the full tax record, not just the headline rate.
Ask an Investor
The Takeaway
Millage rate is the mechanism behind every property tax bill. Understanding how mills stack across taxing bodies and how assessed value differs from market value lets investors calculate true operating costs — not estimates. On a buy-and-hold property, that precision is the difference between a deal that cash flows and one that quietly bleeds.