What is an Animal Unit (AU)?

One Animal Unit equals one 1,000 lb cow with calf. Heavier or lighter animals are converted using a factor (e.g., a 1,200 lb cow = 1.2 AU). This tool uses the standard 1 AU baseline.

What is an Animal Unit Month (AUM)?

One AUM is the amount of forage needed to feed one animal unit for 30 days — roughly 800 lb of dry forage. Pasture capacity is often rated in AUMs per acre per year.

What utilization rate should I use?

Most range managers recommend 25–50%. Semi-arid rangeland typically uses 25–35%; improved pasture up to 50%. Exceeding 50% risks soil compaction, root damage, and long-term yield decline.

Why does forage type matter?

Different grasses produce very different amounts of dry matter per acre. Native rangeland may yield 0.5–1.0 AUM/acre while irrigated bermudagrass can yield 4–6 AUM/acre.

Can I use this for sheep or other livestock?

Yes — convert to animal units first. One sheep ≈ 0.2 AU, one horse ≈ 1.25 AU. Multiply your herd by its AU factor, then check whether the total AU fits within the calculator result.

How accurate are the forage production values?

The built-in values are typical regional averages. Actual production varies by soil type, rainfall, fertilization, and management. For site-specific planning, contact your local NRCS or extension office for measured productivity data.

Cattle Stocking Rate Calculator

Name: Cattle Stocking Rate Calculator
Availability: InStock
Author: Nham Vu

Enter your pasture size, forage type, and utilization rate to get the number of animal units your land can sustainably support.

Pasture Inputs

Pasture Acreage (acres)

Primary Forage Type

Typical annual AUM production for the selected forage.

Utilization Rate: 35%

10% (conservative) 60% (intensive)

25–50% is the standard safe range. Above 50% risks overgrazing.

Planned Grazing Period (months)

How long cattle will graze this pasture (1–12 months).

Animal Unit Weight (lb)

Standard AU = 1,000 lb. Adjust for your herd's average weight.

Grazing Capacity Results

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Max Animal Units

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Estimated Head

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Available AUMs

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Acres per AU

Utilization Rate Guide

Rate	Scenario	Risk
10–25%	Arid rangeland, restoration sites	Very low
25–35%	Semi-arid range, rotational grazing	Low
35–50%	Improved pasture, well-managed	Moderate
50–60%	Intensive irrigated systems only	High — monitor closely

Animal Unit Equivalents

Cow (1,000 lb + calf)1.0 AU

Bull (1,500 lb)1.5 AU

Yearling (600 lb)0.6 AU

Weaned calf (400 lb)0.4 AU

Horse (1,000 lb)1.25 AU

Sheep / goat0.2 AU

Summary

Enter your pasture size, forage type, and utilization rate to get the number of animal units your land can sustainably support.

How it works

Enter the total pasture acreage available for grazing.
Select the primary forage type — each type has a standard AUM/acre production value.
Set the utilization rate (typically 25–50%) to protect root reserves and prevent overgrazing.
Enter the planned grazing period in months.
The calculator divides available AUMs by the grazing period to find the maximum animal units.
Adjust inputs to compare rotational vs. continuous grazing scenarios.

Use cases

Determine safe herd size before expanding cattle operations.
Plan rotational grazing schedules to rest pastures and improve grass health.
Compare stocking capacity across different forage types or seed mixes.
Estimate how long a hay supply will supplement pasture during dry periods.
Prepare documentation for USDA NRCS conservation planning.
Evaluate carrying capacity when purchasing or leasing new rangeland.

Frequently Asked Questions

Last updated: 2026-07-01 · Reviewed by Nham Vu