Acreage Calculator

How to Calculate Acreage

The acreage calculator above estimates land area in acres, square feet, and hectares starting from dimensions measured in feet, then dividing by 43,560 — the number of square feet in one acre. The calculator above handles rectangles, triangles, and circles, and accepts dimensions in feet, yards, or meters. All conversions to feet happen automatically.

Rectangle (most common)

For a rectangular lot: Area (sq ft) = Length (ft) × Width (ft). Then divide by 43,560 for acres. A 660 ft × 66 ft strip equals exactly 43,560 sq ft — 1.00 acre.

Triangle

For a triangular parcel: Area (sq ft) = 0.5 × Base (ft) × Height (ft). The height must be perpendicular to the base — not the length of a slanted side.

Circle

For a circular plot: Area (sq ft) = π × (Diameter ÷ 2)². Enter the diameter (the full width across the circle); the calculator derives the radius internally.

Acreage Conversion Reference — Acres to Square Feet and More

Here are the most commonly needed acreage conversions. Bookmark this table if you work with land measurements regularly:

• 1 acre = 43,560 square feet
• 1 acre = 4,840 square yards
• 1 acre = 4,047 square meters
• 1 acre = 0.4047 hectares
• 1 hectare = 2.471 acres
• 1 square mile = 640 acres
• 1 township (US survey) = 36 square miles = 23,040 acres

When ordering materials like topsoil or gravel for large land areas, start with the acreage and convert to square feet to calculate volume needs.

What Does One Acre Look Like?

One acre covers 43,560 square feet — roughly the area of a standard American football field including the end zones (which measures about 57,600 sq ft, or 1.32 acres). If you picture a square parcel, one acre is approximately 208.7 feet on each side. That's about 70 yards — just over two-thirds the length of a football field in every direction.

Common real-world references for one acre:

• 75% of a standard American football field (playing area only, no end zones)
• About 16 standard tennis courts laid side by side
• Roughly 4–5 typical suburban quarter-acre lots
• A parking lot with space for about 150 cars

Common Land Measurements and How They Compare

US land measurement uses the acre as its primary unit. Here's how common parcel sizes compare:

• Quarter-acre lot (0.25 ac) — 10,890 sq ft, a typical suburban residential lot
• Half-acre lot (0.5 ac) — 21,780 sq ft, common for rural residential or farmettes
• 1 acre — 43,560 sq ft, minimum for many rural septic setbacks and horse properties
• 5 acres — 217,800 sq ft, common small farm or hobby farm size
• 40 acres — 1,742,400 sq ft, a traditional "40" — one-sixteenth of a township section
• 640 acres — one square mile, one full section in the US Public Land Survey System

Internationally, the hectare (10,000 m²) replaces the acre. One hectare equals 2.471 acres. Agricultural land in Europe, Canada, and Australia is quoted in hectares; US farmland is quoted in acres.

Acreage for Farming and Construction Projects

Knowing your acreage is the first step for most outdoor projects. For landscaping, acreage determines how much mulch or fill dirt you need. For farming, it determines seed rates, fertilizer quantities, and irrigation coverage. For construction, zoning rules and setbacks are often expressed as a percentage of lot area or in minimum lot sizes by acre.

Common rules of thumb for large-area projects:

• Seeding a lawn — 1 acre requires 4–8 lbs of grass seed depending on species
• Fertilizing — most fertilizers are dosed by 1,000 sq ft; 1 acre = 43.56 applications of 1,000 sq ft dosage
• Irrigation — a typical drip system covers about 0.5–2 acres per zone
• Clearing — land clearing costs average $1,500–$3,000 per acre for light brush, $3,000–$6,000 per acre for dense forest

Acreage and Zoning — How Lot Size Affects What You Can Build

In most US jurisdictions, minimum lot size is set by zoning ordinance and directly controls what you can build on a parcel. Common zoning categories and their typical acreage requirements:

• R-1 Single-family residential — lots as small as 6,000–10,000 sq ft (0.14–0.23 acres) in urban areas; 0.25–0.5 acres in suburban zones
• Rural residential — typically 1–5 acres minimum, often driven by septic setback requirements
• Agricultural — minimum lot sizes range from 5–20 acres depending on county; smaller lots may prohibit keeping livestock
• Commercial / industrial — minimum sizes vary widely by use and municipality

Beyond the minimum lot size, many zoning codes also impose a floor area ratio (FAR) — the maximum total building square footage as a fraction of lot area. A FAR of 0.5 on a 1-acre lot would allow up to 21,780 sq ft of total building area. Always verify acreage with a survey before purchasing land for development.

How to Measure Acreage Without a Surveyor

Several methods can estimate lot acreage without professional equipment:

• Walk-off measurement — pace the perimeter of a rectangular lot (one normal walking step ≈ 2.5 feet) to estimate dimensions. Accurate to within 5–10% for rectangular parcels.
• Online satellite tools — Google Maps' "Measure distance" feature and similar tools allow you to trace a polygon over satellite imagery. Useful for approximate planning; not legally binding.
• County GIS / tax records — most county assessor websites publish parcel maps with acreage figures. Free and useful for a quick reference, though dated surveys may have minor errors.
• Measuring wheel — a rolling measuring wheel gives accurate linear measurements for boundary lengths. Combine with this calculator for precise area estimates.
• GPS survey app — smartphone apps like GPS Fields Area Measure or AcreCalc use GPS location data to trace the perimeter of a parcel. Accuracy varies by GPS signal quality but is typically within 2–5% for open areas.

For any legal purpose — property sale, subdivision, permitting, or boundary disputes — a survey by a licensed land surveyor is required. DIY methods are for planning estimates only.