Home › Paddock Planner

Rotational Grazing Paddock Calculator

How many paddocks your rotation needs and how big each one should be — with intake and utilization kept honest.

How many paddocks, how big

Paddock count: WVU Extension — paddocks = (rest ÷ graze) + 1, rounded up. Intake, utilization, and forage math: Univ. of Kentucky, "Using a Grazing Stick." Reviewed July 2026

The two formulas doing the work

Paddock count is the classic rotation identity: paddocks = (rest days ÷ grazing days) + 1 — the +1 is the paddock the herd is standing in while the others rest. 30 days of rest at 3-day moves = 11 paddocks. Fractional answers always round up: 10.5 paddocks means 11, because rounding down shorts your rest period.

Paddock size comes from supply and demand: the herd needs (herd weight × intake %) pounds of dry matter per day, and each acre offers (standing DM × utilization). Days × demand ÷ per-acre supply = acres per paddock. Note that intake and utilization are separate numbers — intake is what the animals eat; utilization is the share of standing forage they can harvest before residual, rejection, and trampling stop them. Counting waste in both places double-counts it.

Worked example: 20 cows × 1,200 lb = 24,000 lb herd at 3% = 720 lb DM/day. Pasture at 2,400 lb DM/acre with 62.5% utilization offers 1,500 usable lb/acre. Three-day paddocks: 720 × 3 ÷ 1,500 = 1.4 acres per paddock, × 11 paddocks ≈ 16 acres in the rotation.

Rest is seasonal: cool-season pastures regrow fast in spring and slow in summer — many graziers run shorter rests in May and stretch them out past 40 days in August. Set the rest input to the season you're planning, not an annual average.