Winter Hay Calculator — How Many Bales Needed?

Hay calculator (winter feed planning)

Fill in the fields above and press Calculate.

The calculation, step by step

Hay per horse per day = body weight × % of body weight fed as hay Total consumed = hay per horse per day × number of horses × days Hay to buy = total consumed × (1 + waste allowance) Bales = hay to buy ÷ bale weight, rounded up

At 2% of body weight, one 1,000 lb horse eats 20 lb of hay a day. Over a 150-day winter that is 3,000 lb — 60 square bales of 50 lb for a single horse, before any waste.

A worked example

Two horses averaging 1,000 lb, fed 150 days, at 2% of body weight, with 10% waste allowance, in 50 lb bales at $8:

20 lb/day × 2 horses × 150 days = 6,000 lb consumed +10% waste = 6,600 lb to buy 6,600 ÷ 50 = 132 bales × $8 = $1,056

Waste is not optional

Hay fed on the ground, in the rain, or from an open ring is wasted at rates from 5% to over 30%. Common findings from feeding trials:

Method	Typical waste
Fed on the ground, outdoors	20–30%
Open ring feeder	10–20%
Covered feeder with a basket	5–10%
Small-hole slow feeder	under 5%

Upgrading the feeder usually pays for itself within one winter, and slow feeders also stretch eating time, which is good for the gut.

Cold weather changes the maths

For every degree below about 5 °C (41 °F), a horse’s energy requirement rises, and the increase becomes substantial in hard frost and wind. Feeding extra hay rather than extra grain is the safer response: the fermentation of fibre in the hindgut generates heat, which is exactly what a cold horse needs.

Rule of thumb: below freezing, add roughly 10–20% more hay. Add a bale or two to your order rather than being caught short — hay is heaviest and most expensive exactly when everyone runs out.

Frequently asked questions

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

At 2% of body weight, a 1,000 lb horse eats about 20 lb of hay a day, so a 150-day winter needs about 3,000 lb — roughly 60 bales of 50 lb, plus a waste allowance.

How much hay does a 1,000 lb horse eat per day?

About 15–20 lb per day for a horse at maintenance, depending on weather and body condition. It should be at least 1% of body weight, ideally closer to 2%.

How much hay waste should I allow for?

Budget 10% with a good covered feeder, 20–30% if hay is fed on the ground outdoors. Weighing what is left in the field is the only way to know your own figure.

Should I feed more hay or more grain in cold weather?

More hay. Digesting fibre generates body heat, so extra forage warms a horse as well as feeding it, whereas extra grain raises the risk of digestive upset.

Related tools and guides

Sources and method

Equine extension guidance on feeding 1.5–2.5% of body weight per day, with a minimum of roughly 1% as long-stem forage.
Ontario Ministry of Agriculture, Food and Rural Affairs — Estimating body weight for horses (for the weight figure rations are based on).

Page last reviewed 2026-10-16. Results are estimates from published formulas and are not veterinary advice.