What this calculator does
A head count tells you very little on its own, because a dry cow, a lactating cow and a weaner do not eat the same amount. Stocking rate solves that by converting animals into standard units first. Two hundred head at eight units each on 120 grazeable hectares is 13.33 units a hectare, and against land rated at 12 that is over capacity by 1.33.
The number that actually makes the decision is the last one: the land supports 180 head of that class, not 200. Overstocking does not announce itself in the first season. It shows up as lost ground cover and a feed bill the following year, by which point the paddock takes longer to recover than it took to overgraze.
The formula
Animals become comparable units through head × units per animal, and the stocking rate is total units ÷ grazeable hectares. Capacity is the other direction: hectares × carrying capacity gives the units the land will carry, and dividing that by the units per animal gives a head count. The calculator does not care which unit system you use, dry sheep equivalents or animal units, as long as the per-animal figure and the carrying capacity come from the same one.
| Term | Meaning |
|---|---|
| Animal unit | A standard eating animal. DSE in Australia and AU in North America are the two common systems. |
| Stocking rate | Units carried per hectare. What you are doing. |
| Carrying capacity | Units a hectare can support without degrading. What the land will take. |
| Grazeable area | Hectares stock can actually eat, which is less than the title area. |
The inputs explained
| Field | What to enter |
|---|---|
| Number of animals | Number of animals in the mob. |
| Units per animal | Units per animal for that class of stock, from the same rating system as the carrying capacity below. |
| Grazeable area (ha) | Grazeable hectares only. Take out dams, tracks, timber, rock and anything fenced off. |
| Carrying capacity of the land (units/ha) | Carrying capacity for your land in a normal season, from local extension figures or your own records. |
When to use it
Checking a mob against a paddock
Enter the head count, the unit rating for that class and the grazeable area. If the rate is over capacity, the head the land supports tells you how many to move.
Working out what to buy
Read the head the land supports and treat it as the ceiling for a normal season, then buy under it so a dry spell does not force a sale.
Comparing two properties
Stocking rate per hectare is the only fair comparison between blocks of different sizes and different stock classes, which is what the unit conversion is for.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How many head can 120 hectares carry?
Only the number of animals changes.
| Number of animals | Stocking rate | Against capacity | Hectares per animal |
|---|---|---|---|
| 120 head | 8.00 units/ha | within capacity, 4.00 units/ha spare | 1.00 |
| 160 head | 10.67 units/ha | within capacity, 1.33 units/ha spare | 0.75 |
| 180 head | 12.00 units/ha | within capacity, 0.00 units/ha spare | 0.67 |
| 200 head | 13.33 units/ha | over capacity by 1.33 units/ha | 0.60 |
| 240 head | 16.00 units/ha | over capacity by 4.00 units/ha | 0.50 |
What does a change in carrying capacity do?
The mob and the area are fixed and only the capacity of the land changes.
| Carrying capacity | Against capacity | Units the land supports | Head the land supports |
|---|---|---|---|
| 6 units/ha | over capacity by 7.33 units/ha | 720 | 90 |
| 8 units/ha | over capacity by 5.33 units/ha | 960 | 120 |
| 10 units/ha | over capacity by 3.33 units/ha | 1,200 | 150 |
| 12 units/ha | over capacity by 1.33 units/ha | 1,440 | 180 |
| 15 units/ha | within capacity, 1.67 units/ha spare | 1,800 | 225 |
Questions
DSE or AU, which should I use?
Either, as long as both inputs use it. Dry sheep equivalents are standard in Australia and animal units in North America, and mixing a DSE rating with an AU carrying capacity will be wrong by roughly a factor of seven.
How do I find the units per animal?
From a local rating table for the class and weight of stock, because it depends on liveweight and whether the animal is growing, pregnant or lactating. The same cow can be a very different number across a year.
Where does carrying capacity come from?
Local extension or departmental figures for your rainfall and pasture type, adjusted by your own records. It is not a property of the land alone: it moves with the season, so a figure from a good year will overstock a poor one.
Is this the same as the carrying capacity calculator?
No. The logistic growth page models how a wild population approaches a ceiling over time. This one compares the stock you are running now against a grazing capacity you supply, which is a management figure rather than a population model.
Should I plan to sit right on capacity?
Most graziers plan under it, because capacity is an average and the bad seasons are what force decisions. Running at capacity in a normal year means destocking or feeding in a dry one.
For population dynamics rather than grazing pressure, see logistic population growth. Animal mortality rate covers losses across a period, and tree carbon storage handles the timber on the block.