Pasture Stocking Density Calculator
Overstocking damages pastures through overgrazing, soil compaction, and erosion, while understocking wastes forage and reduces efficiency. The USDA NRCS stocking rate calculation divides available forage (total production x use factor) by the daily forage demand per animal unit times the number of grazing days. The result is the maximum stocking density in animal units per acre. This calculator implements the standard NRCS formula and uses 26 lb dry matter per day as the standard daily demand for one animal unit (AU), defined as a 1,000-lb beef cow.
Stocking density formula
Available forage (lb/acre) = Annual production x (Use factor / 100)
AU per acre = Available forage / (26 lb/day x Grazing days)
Total AU = AU per acre x Acres
One animal unit (AU) = 1,000-lb beef cow consuming 26 lb dry matter per day (USDA NRCS standard). Adjust for other species: multiply AU demand by AU equivalents (horse = 1.25; sheep = 0.20).
Animal unit equivalents (USDA NRCS)
- Beef cow (1,000 lb): 1.00 AU.
- Dairy cow (1,400 lb): 1.40 AU.
- Horse (1,250 lb): 1.25 AU.
- Sheep or goat (125 lb): 0.20 AU.
- Hog (150 lb): 0.30 AU.
- Beef calf (400 lb): 0.40 AU.
Pasture stocking density calculator: frequently asked questions
What is an animal unit (AU)?
An animal unit (AU) is a standardized measure used by USDA NRCS equal to one 1,000-pound beef cow with or without a calf consuming approximately 26 pounds of dry forage per day. Other livestock are converted to AU equivalents: one horse = 1.25 AU; one sheep or goat = 0.2 AU; one dairy cow = 1.4 AU.
How do I calculate stocking rate?
Stocking rate = Total AU / Total acres. For example, if your pasture produces 2,000 lb dry matter per acre per year and you harvest 50 percent, that is 1,000 lb per acre for grazing. At 26 lb per day per AU for 200 grazing days, each AU needs 5,200 lb: 1,000 / 5,200 = 0.19 AU per acre, or 5.2 acres per AU.
What is a safe use factor for forage?
USDA NRCS recommends using only 25 to 50 percent of standing forage (use factor 0.25 to 0.50) to maintain plant health and allow regrowth. Heavy use above 70 percent degrades pasture long-term. The most common recommendation is 50 percent utilization for rotational grazing and 25 to 30 percent for continuous grazing.
How does rotational grazing increase stocking density?
Rotational grazing allows forage plants to rest and regrow between grazing periods. Well-managed rotational systems can support 30 to 50 percent more animal units per acre than continuous grazing of the same pasture by maximizing forage utilization efficiency.
Where do I find forage production data for my area?
USDA NRCS Web Soil Survey (websoilsurvey.nrcs.usda.gov) provides county-level forage production estimates by soil type. Your local Cooperative Extension office also publishes pasture production tables for common grass and legume species in your region.
Official sources
- USDA NRCS, grazing land management: nrcs.usda.gov.
- USDA NRCS, National Range and Pasture Handbook: nrcs.usda.gov.
Reviewed by the CalculatorHub team, edited by James Graham, 15 June 2026. See our methodology.