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Grazing Land Requirement Calculator

Work out grazing land requirement instantly with clear inputs, formula shown and shareable results.

About Grazing Land Requirement Calculator

Grazing area is annual forage demand divided by usable forage per hectare. Only part of what grows can be eaten — the take-half-leave-half rule puts utilisation near 50% for sustainable grazing, because leaving residual leaf area is what allows the pasture to regrow.

Formulas

Grazing demand

Annual demand = animal units x daily intake x 365

Land requirement

Usable forage = yield x utilisation %; land = demand / usable forage

Worked example

With the default values below, Grazing Land Requirement Calculator returns Grazing Land Required of 60.225. Change any input above and every figure here is recalculated in your browser.

Inputs used

Animal Unitsminimum 0.1
30
Dry Matter Intake Per Animal Unitminimum 0.1 kg/day
11 kg/day
Pasture Dry Matter Yieldminimum 1 kg DM/ha/year
4,000 kg DM/ha/year
Utilisation Rateaccepts 5–100 %
50 %

Results

Grazing Land Required
60.225
Annual Forage Demand
120,450
Usable Forage Per Hectare
2,000
Carrying Capacity
0.498

Step by step

  1. 1Values used
  2. 2Grazing demand
  3. 3Land requirement
  4. 4Grazing Land Required= 60.225
  5. 5Annual Forage Demand= 120,450
  6. 6Usable Forage Per Hectare= 2,000
  7. 7Carrying Capacity= 0.498

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

What is an animal unit?

Conventionally a 450-500 kg cow with calf, consuming about 11-12 kg of dry matter a day. Other classes are converted with animal unit equivalents — a dry cow is around 0.9, a yearling 0.7, a ewe 0.15.

Why not graze at higher utilisation?

Grazing beyond about 60% removes the leaf area the plant needs to regrow, shifts the sward to weeds and shallow-rooted species, and cuts long-term productivity even though it feeds more animals this season.

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