Hay Calculator: How Much Hay for Winter

Enter your animals and how many days you'll feed hay. You get the number of bales and tons, and the cost, with waste included.

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Hay Calculator · HerdMath

How it works

Most livestock eat about 2–3% of their body weight in hay each day when hay is all they get. A 1,000 lb horse eats about 20 lb a day, a 1,200 lb cow about 30 lb. Add waste from feeding (5% in a good hay feeder, 25% or more when fed on the ground) and the total climbs fast.

How to use it

Count the days you'll feed hay, from when grazing runs out until spring growth. Weigh a few bales if you can, since actual bale weights vary a lot.

Reference chart

AnimalTypical weightHay per day
Beef cow1,200 lbabout 30 lb (2.5%)
Horse1,000 lbabout 20 lb (2%)
Goat150 lbabout 5 lb (3.5%)
Sheep150 lbabout 4.5 lb (3%)
Donkey450 lbabout 8 lb (1.75%)

Frequently asked questions

How many bales of hay does a horse need for winter?

A 1,000 lb horse eats about 20 lb of hay a day. Over 150 days, with 15% waste, that's about 3,500 lb: roughly 70 small square bales or 4–5 round bales of 800 lb.

How much hay does a cow eat per day?

About 2.5% of body weight, so a 1,200 lb cow eats about 30 lb a day. Lactating cows eat more.

How much hay is wasted?

Feeding on the ground can waste 25% or more. Round bale feeders and hay nets can cut waste to about 5–15%.

How much does a round bale weigh?

It varies with size, hay type and moisture. A 4×5 round is often 700–900 lb and a 5×6 round 1,000–1,400 lb. Weigh a few bales to know for sure.

Figures are typical values from university extension and breed-association guidance. Estimates only. Individual animals vary — confirm pregnancy and health questions with your veterinarian. Last reviewed 2026-09-18.