To find how many units can be built on a parcel, turn every limit in the zoning rules into a number of units or a floor area, then take the smallest. The limit that gives the smallest number is the one that binds, and it is the only one that matters for that parcel. Density gives units directly, floor area ratio (FAR) gives floor area, and coverage, height, minimum lot area and maximum unit size can each cap the result too. Two real parcels below show opposite answers: on one, density binds at 1 home; on the other, FAR binds at 23 units while density would have allowed 40.
Written by the Titleman team with AI assistance (Claude). Reviewed by the Titleman review desk. The figures come from two finished feasibility runs on a Titleman QA account, on real lots with the addresses left out, read on 15 October 2026. A zoning screen is not a zoning verification letter, an appraisal or a design.
The method in 5 steps
- Get the lot area from the record, not the listing. Every limit below is multiplied by it. Listings round, and a lot can be recorded smaller or larger than advertised.
- Find the district and read its rule table in the zoning code in force. Note the date you read it. Rules can differ by street inside one district, and a table for a street can say that it prevails over the general table for the district.
- Convert each limit to units or floor area. The table below shows how.
- Take the smallest result. That is the binding limit. Write down which one it is, because it tells you what to ask for: a variance, a lot assembly, or nothing at all.
- Check what the table cannot see. Historic review, flood and coastal rules, setbacks, parking and a pending plan can all lower the answer. Ask the city for a zoning verification letter before you pay for design.
| Limit | How to turn it into a number | Result is in |
|---|---|---|
| Density (units per acre) | lot area in SF ÷ 43,560 × units per acre, rounded down | units |
| FAR | lot area × FAR | SF of floor area |
| Floor area to units | floor area × efficiency ÷ average unit size, rounded down | units |
| Lot coverage | lot area × coverage % × number of storeys the height allows | SF of floor area |
| Height | height ÷ floor-to-floor height, rounded down, gives the storeys | storeys |
| Minimum lot area | lot area ÷ minimum lot area, rounded down | lots |
| Maximum unit size | often a share of the lot area | SF per unit |
Two cautions. First, a density limit counts dwellings and a FAR counts floor area, so you need an average unit size to compare them; state it, because the answer moves with it. Second, a district can set no FAR at all and limit buildings by unit size, coverage and height instead. Then there is no FAR to look up, and the table is the answer.
Parcel 1: density binds (a 16,000 SF lot in a single-family district)
A Titleman feasibility run asked what could be built on an oceanfront vacant lot in Miami Beach. The rules it read for the lot:
| Limit | Value | What it gives on 16,000 SF |
|---|---|---|
| Density | 4.35 units per acre | 0.367 acres × 4.35 = 1.6, so 1 home |
| Minimum lot area | 10,000 SF | 1 lot; a split would need 20,000 SF |
| Maximum unit size | 50% of lot area | 8,000 SF |
| Lot coverage, two-storey home | 30% | 4,800 SF footprint |
| Height | 24 ft, flat roof | two storeys |
| FAR | none set | the district limits buildings by unit size, coverage and height |
The binding limit is density, and the lot-area rules agree with it. Density gives 1.6 homes, which rounds down to 1. A second home would need about 20,000 SF by density (2 ÷ 4.35 acres), which is the same area the minimum-lot rule requires for a split. The 16,000 SF lot falls 4,000 SF short of both.
The other limits then shape that one home. Two full storeys on the 4,800 SF footprint would be 9,600 SF, so the 8,000 SF unit-size cap bites before the footprint does. Looking up a FAR here would have found nothing, which is why a lookup that returns only a zone name stops before the answer.
The run also listed what the table could not settle: the lot sits in a historic district, so the design needs the historic board's approval; the rear setback on the water side could not be read in the code text; and a state coastal permit was likely. It assumed 12 months for design and approvals before a 24-month build.
Parcel 2: FAR binds (a 17,500 SF lot on a commercial corridor)
A second run covered a lot on a commercial street in the same city. The street's rule table gave:
| Limit | Value | What it gives on 17,500 SF |
|---|---|---|
| FAR | 1.5 | 17,500 × 1.5 = 26,250 SF |
| Density | 100 units per acre | 0.402 acres × 100 = 40.2, so 40 units |
| Height | 55 ft | 5 storeys at 11 ft floor-to-floor |
| Lot coverage | not read | the run says so |
To compare the two, the run used its stated assumptions of 80% saleable area and a 900 SF average unit. That makes 26,250 × 0.8 = 21,000 SF, which divides into 23 units. Density would have allowed 40.
The binding limit is FAR. To fit 40 units of 900 SF the building would need 45,000 SF of gross floor area, a FAR of 2.57, against the 1.5 the table gives. The density limit had 17 units of room that the floor area could not use. Changing the unit size changes the count: smaller units fit more, larger units fewer.
The seller's FAR did not match the code in force
The request that started the run stated two things about the lot: the existing building used a FAR of about 1.5, and zoning allowed 4.0. The run checked both against records:
| Item | Stated | Found |
|---|---|---|
| FAR the code allows | 4.0 | No rule in the code in force gives this lot more than 1.5. A higher FAR is under discussion in a pending city plan, and the stated figure may come from it. |
| FAR of the existing building | about 1.5 | 0.43: 7,552 SF recorded on a 17,500 SF lot |
The two errors point in opposite directions. At the stated 4.0 the lot would carry 70,000 SF, and by area alone 62 units, but density would cap it at 40. So the claimed FAR would have flipped the binding limit from FAR to density. And if the building had really used a FAR of 1.5, nothing would be left to build; at 0.43 it leaves 18,698 SF of unused floor area. The run kept the stated figures in the answer beside the records, and flagged that the whole study depends on which is right.
The run also reported where the sources disagreed: a general table for the district gave a higher FAR for mixed-use buildings, while the street's own table gave 1.5 and said it prevails in a conflict. It used 1.5 and marked the reading as one to confirm with a zoning letter.
The two parcels side by side
| Item | Parcel 1 | Parcel 2 |
|---|---|---|
| Lot | 16,000 SF | 17,500 SF |
| Binding limit | Density | FAR |
| Result | 1 home | 26,250 SF, 23 units at 900 SF |
| The limit that did not bind | Unit size, coverage and height shape the home | Density, 40 units |
| What would change it | A lot of about 20,000 SF | A different FAR, or smaller units |
| Check against the stated number | None needed | Stated FAR 4.0 not in the code; building FAR 0.43, not 1.5 |
How to look up zoning and FAR for a specific parcel
The lookup has three parts, and most tools only do the first.
- The district for the address. A zoning map or lookup returns a zone name. This is the easy part, and it is where a zone-name lookup stops.
- The rule table for that district, as it stands today. Read density, FAR, coverage, height, setbacks and minimum sizes from the zoning code in force, not from a summary or a plan under discussion.
- The parcel's own numbers. Lot area from the record, and the existing building's area, so you can see how much floor area is already used.
For tools that cover the first part, see zoning lookup tools by address. For general background on the ratio, see floor area ratio, zoning in the United States and setbacks.
What the count does not tell you
- Whether it is worth building. Units are an input to value, not the value. Take the count to a feasibility model and see how to calculate residual land value. In the second run, the residual changed sign with build cost alone.
- Whether the rules are what the city will apply. The first run could not read the water-side setback in the code text; the second read its FAR from a copy of the code and marked it for confirmation.
- Whether approvals will come. Historic review, in both runs, decides whether the existing building can be removed or what can replace it.
For a full screen of a site, see land feasibility software, which reads the rules, runs the limits on the parcel and lists what it could not establish.
To see every limit checked on a parcel you know, request a demo.
Frequently asked questions
How do you estimate how many units can be built on a parcel under zoning? Turn each limit in the zoning rules into a number of units or a floor area, then take the smallest result. Density gives units directly: lot area in acres times the units per acre, rounded down. Floor area ratio gives floor area: lot area times the ratio, which you divide by an average unit size and an efficiency factor to get units. Coverage, height, minimum lot area and maximum unit size can each cap the result as well. The limit that gives the smallest answer is the one that binds.
How can you look up zoning and FAR for a specific parcel in the United States? First get the lot area and the zoning district for the address from the property record and the city zoning map. Then find the rule table for that district in the zoning code in force and read density, FAR, coverage, height and setbacks from it. Rules can differ by street within one district, some districts set no FAR at all, and a pending plan is not the code in force. A zoning verification letter from the city settles any remaining doubt.
What if the seller says the parcel is zoned for a higher FAR? Check it against the code in force before using it. In the run described on this page, a request stated that zoning allowed a FAR of 4.0. No rule in the code in force gave that lot more than 1.5, and the recorded building was a FAR of 0.43, not the 1.5 stated. A higher figure can come from a pending plan or from a different district, and it changes the answer: at 4.0 the density limit would bind instead of the FAR.
Is the zoning-based unit count the number you can actually build? It is the ceiling the zoning rules set, not a design. Historic review, flood rules, coastal permits, parking, setbacks and the market can all lower it. Treat the count as a screen to decide whether a site deserves an architect's time, and confirm it with a zoning verification letter.
Written by the Titleman team with AI assistance (Claude). Reviewed by the Titleman review desk. Figures read from two finished runs on a Titleman QA account (made on 5 and 7 October 2026) on real lots, with the addresses left out, on 15 October 2026. Rules were read from the zoning code in force on the run dates and are not confirmed by a zoning verification letter. The assumptions of 80% saleable area and a 900 SF average unit are the run's own, not a rule.