How to calculate upland acres, and why land should be priced by them
Two tracts can both be 100 acres and be worth very different amounts. The difference is usually how much of each one you can actually build on.
Upland acres, in one sentence
Upland acres are the part of a tract that is dry ground: the acreage left after you take out wetlands. It is the acreage a builder or developer can usually put lots, roads and buildings on, so it is the acreage that drives what the land is worth.
Upland acres = gross acres × (1 − wetland share)
Price per upland acre = price ÷ upland acres
A worked example
An owner is asking $1,260,000 for a 120-acre tract. A wetland screen shows about 36 acres of wetland, or 30% of the tract.
- Upland acres: 120 × (1 − 0.30) = 84 acres
- Price per gross acre: $1,260,000 ÷ 120 = $10,500
- Price per upland acre: $1,260,000 ÷ 84 = $15,000
Now compare it with three nearby sales:
| Sale | Acres | Wetland | Upland acres | Price | Per gross acre | Per upland acre |
|---|---|---|---|---|---|---|
| A | 60 | 10% | 54 | $1,080,000 | $18,000 | $20,000 |
| B | 100 | 45% | 55 | $1,100,000 | $11,000 | $20,000 |
| C | 40 | 0% | 40 | $760,000 | $19,000 | $19,000 |
By gross acre, the sales run from $11,000 to $19,000, which tells you almost nothing. By upland acre they sit between $19,000 and $20,000. At about $19,500 per upland acre, the 84 upland acres in the example point to roughly $1.64 million, well above the $1.26 million asking price. The gross-acre view would never have shown that.
The numbers above are made up to show the math. This is not an appraisal or a valuation: confirm wetlands with an on-site delineation and price land with a qualified appraiser or broker.
How to calculate upland acres, step by step
- Start with gross acres. Take the acreage from the county record, then check it against the deed and any recorded plat. A new survey wins when you have one.
- Screen for wetlands. The U.S. Fish and Wildlife Service’s National Wetlands Inventory maps are the usual first look. Measure how much of the parcel the mapped wetlands cover.
- Subtract the wetland share. Gross acres × (1 − wetland share) gives your upland estimate.
- Price it per upland acre. Divide the asking price, or your offer, by upland acres.
- Do the same to every comparable sale. A comp priced per gross acre next to a subject priced per upland acre is a mismatch.
What a wetland screen can and cannot tell you
The National Wetlands Inventory is a screening tool. The Fish and Wildlife Service says its maps use a biological definition of wetlands that may not match the federal regulatory one, and that an on-the-ground inspection can change the boundaries (U.S. Fish and Wildlife Service). Use it to rank and price tracts early. Before you close, have a consultant delineate the wetlands on site and confirm the lines with the U.S. Army Corps of Engineers.
A few things that are not wetland can still cut into what you can build:
- Flood zones. Flood-zone ground is often still upland, but building in it costs more. Track it separately rather than subtracting it.
- Buffers. Many towns and counties require a setback from wetlands and streams. The buffer comes off your usable ground.
- Easements and rights-of-way. Power lines, pipelines and road widening all take usable acres.
Put upland acres in your offer
Because the true wetland line is only known after delineation, many land contracts set the price per upland acre and adjust the total once the survey and delineation are done. If you write the price that way in your letter of intent, nobody has to argue about it later. Our guide to land letters of intent covers the wording.