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How the Number Is Built

Every valuation on this site comes from public records and recorded sales, and this page shows you exactly which ones and exactly what happens to them. If a number cannot be checked, it is not worth much — so here is the whole method, including what it does not know.

Where the data comes from

Three public sources, refreshed from the state files. Nothing here is proprietary in the sense of being secret; it is proprietary in the sense that assembling it took a year.

SourceWhat it provides
Florida Department of Revenue
Name-Address-Legal roll (NAL)
Parcel ID, owner of record, situs address, DOR use code, year built, unit count, just value, last sale price and date. 15,999 properties coded 10+ units and 158,214 smaller multifamily parcels, all 67 counties.
Florida Department of Revenue
Sale Data File (SDF)
Recorded sale price, month, year, and the state qualification code that separates arms-length transfers from family, foreclosure and corporate-restructuring transfers. 8,206 qualified sales in the current file.
15,999Florida apartment properties of 10+ units
1,393,995Apartment units tracked statewide
8,206Qualified arms-length Florida sales in the current state file

Counts as of August 2026, across all 67 Florida counties.

What the market's number actually does

It is an income capitalization, run the same way a buyer's analyst would run it, on the data available before anyone has spoken to you.

Step 1 — Gross potential rent

Your occupied units multiplied by your actual rent. Not the market rent someone thinks you could charge, and not the county average — what is being collected today. This is why the valuator asks for a figure rather than a range: a $200 spread on a 16-unit building is a swing of roughly $550,000 in value at a 7 cap, which is more than most owners expect.

Step 2 — Other income and vacancy

Laundry, parking, storage, pet and utility reimbursements. Then vacancy and collection loss comes off, using your occupied-unit count rather than a stock 5%.

Step 3 — Operating expenses

Property tax at the county millage that will apply after the sale resets the assessment, insurance at what a new owner will be quoted rather than what your renewal happened to be, management whether or not you pay for it today, repairs, turnover, and utilities net of reimbursement. Management is included even for owner-operators, because a buyer's lender will underwrite it whether you take a salary or not.

Step 4 — Capitalize

Net operating income divided by the cap rate buildings in your county are actually trading at, taken from qualified sales in the state file rather than from a survey of broker opinions. Age, unit mix, construction type and location all move that rate, and the range you see reflects the spread of real transactions rather than a confidence interval from a formula.

What it does not know

This is the part most valuation tools leave out, and it is the part that matters. The market's number is built from records. Records do not contain the following, and every one of them can move the figure by more than the model's own precision.

That gap is the entire reason for the second number. The market's number tells you the neighborhood you are in. The bank's number — what a lender will actually finance — requires the twenty minutes of conversation the records cannot substitute for.

Why the bank's number is usually lower

A buyer's lender underwrites to what will still be true after the sale, not what was true while you owned it. Three things reliably move against a seller:

A broker who leaves those three alone can hand you a number 10 to 15 percent higher and win your listing with it. Then the appraisal comes in, the financing gaps, and you are renegotiating from a weaker position than the one you started in. I would rather show you the lower number now.

How accurate is it

Honestly: it is a starting point, and it is presented as a range for that reason. Where the model has your real rent and a good occupancy figure it is usually close. Where it is inferring from the tax roll alone it can be well off, particularly on buildings with unusual configurations. It is not an appraisal, it does not pretend to be one, and no lender will accept it as one.

The right way to use it is as a filter: if the range is nowhere near what you had in mind, you have learned something for free in about a minute. If it is close, the next step is worth taking.

Citing this page

How to cite: Minchin, Christopher. "How the Number Is Built: Apartment Building Valuation Methodology." The Apartment King, August 2026. https://theaptking.com/methodology.html

Underlying public sources: Florida Department of Revenue property tax data portal (Name-Address-Legal roll and Sale Data File). Figures stated on this page are counts from those files as loaded in August 2026 and will change as the state republishes them.

Under section 475.612(3), Florida Statutes, a licensed real estate broker may prepare a comparative market analysis or opinion of value. In no event may it be referred to or construed as an appraisal. If you need an appraisal — and for most institutional financing you will — that is a separate engagement with a state-certified appraiser, and I am happy to tell you who I would call.

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