Pasture Stocking Rate Calculator

An animal unit (AU) is a standard grazing animal, conventionally a 1000 pound cow with a calf. It eats about 26 pounds of dry forage a day, roughly 2.6 percent of body weight, which is the default intake this tool uses. Larger or lactating animals count as more than one AU.

Usable forage equals acres times forage per acre times utilization. Animal units supported divides that usable forage by daily intake times grazing days. In the reverse mode, forage needed equals animal units times intake times days, and acres needed divides that by forage per acre times utilization.

A common planning figure is 50 percent, leaving half the standing forage as residue for regrowth, root reserves and soil cover. Tightly managed rotational grazing can push utilization higher, while continuous set stocking usually runs lower. Utilization must be between 1 and 100.

Clip and weigh several representative sample plots, dry the clippings, and scale up to a per acre dry matter figure, or use local extension yield tables for your forage species and rainfall. Standing forage varies hugely by species, season and soil, so measure on your own ground when you can.

Yes. Weigh or estimate each class of stock and divide by 1000 pounds to get its AU value, then sum the herd. A 1300 pound cow is about 1.3 AU, and a group of stockers is the sum of their individual fractions. Enter that total in the Animal units field.

No. It treats the standing forage as a fixed budget for the period you enter. Over a long graze in a growing season, regrowth adds forage the model does not count, so a short period is easier to estimate accurately than a whole season.

Yes. The Intake field defaults to 26 pounds per AU per day but you can override it, for example to model higher intake on lush spring pasture or a different class of livestock. Intake must be a positive number.

No. It is a first pass planning estimate that ignores trampling loss, weather swings, forage quality and animal selectivity. Use it to set a starting stocking rate, then adjust with your own pasture monitoring and local extension guidance.

Yes. Every calculation runs locally in your browser with no login and no upload, so your acreage and herd numbers stay on your device.