How much hay a horse eats each day and how much to buy for the season, with feeder waste and storage loss included, converted to small squares, round bales and dollars.
Horse Hay Calculator - Hay per Day, Bales and Tons a Year
How much hay a horse eats each day and how much to buy for the season, with feeder waste and storage loss included, converted to small squares, round bales and dollars.
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How much hay a horse eats, and how much you have to buy
Enter the horse's weight, or two tape measurements, pick a daily rate, the feeder and where the hay is stored. The horse hay calculator returns pounds per day, tons for the season and the number of bales to order, with the waste of your feeder and your storage added on top. A 1,000 lb horse at 2% of body weight eats 20 lb of hay a day, but the order for a year is closer to 8,125 lb than to 7,300.
Ordering by rule of thumb
- "A bale a day" ignores that bales of the same size can weigh 40 lb or 75 lb.
- The total covers what the horse eats, not what ends up trampled or moldy.
- Pasture months get counted as hay months, or the other way round.
- The weight of the horse is a guess, and every pound of guess is 0.02 lb of hay a day.
Ordering with the calculator
- Body weight from a scale, or from heart girth and body length.
- Feeding waste from University of Minnesota feeder trials, from 1% to 57%.
- Storage loss from 6% in a barn to 37% uncovered on the ground.
- Bales for your own bale weight and price, plus four common sizes.
Nine boxes, and which of them you can skip
- Horse weight - pounds from a livestock scale or a vet clinic. Leave it empty if you only have a tape.
- Heart girth and body length - inches, for the tape estimate. Girth goes just behind the elbows and over the withers after the horse breathes out; length runs from the point of the shoulder to the point of the buttock.
- Daily hay rate - 2% is the usual planning figure, 1.5% the recommended floor, 2.5% close to the most a horse will eat.
- Number of horses - for a group of similar size. A pony and a draft horse are better run separately.
- Days on hay - only the days hay is the main feed, for example 180 from November to April. Empty means 365.
- Feeder - four ways to feed small squares and four for round bales.
- Storage - barn, covered or not, on the ground or raised, or bought as needed.
- Bale weight and price - optional. With both, the result adds the cost per 30 days and per ton.
Where the hay total comes from
The daily amount is a share of body weight. The amount to buy is that share times the days, then raised twice: once for what the horse pulls out of the feeder and wastes, once for what spoils in storage. This is the same order of steps as the University of Maryland Extension winter hay worksheet.
hay to buy = hay per day × days × (1 + feeding waste) × (1 + storage loss)
weight from tape (lb) = girth² × length / 330 (inches)
Two horses of 1,100 lb, round bales. Rate 2.25%, 150 days, ring feeder (19%), net wrapped bales on the ground (19%). Per day 2 × 1,100 × 0.0225 = 49.5 lb. To buy: 49.5 × 150 × 1.19 × 1.19 = 10,515 lb, or 5.26 tons and 14 round bales of 800 lb.
No scale, only a tape. Heart girth 70 in, body length 66 in: 70² × 66 / 330 = 980 lb. At 2% that is 19.6 lb of hay a day.
A mini on a tight ration. 250 lb, rate 1.75%, a full year, basket feeder, barn. Per day 4.4 lb; to buy 1,743 lb, which is 35 small squares of 50 lb.
What a better feeder and a roof save over one winter
Every row is one horse of 1,000 lb at 2% for 180 days, so it eats 3,600 lb either way. Only the waste changes. The dollar column uses an example price of $250 per ton; enter your own bale price in the calculator for your figure.
| Change | Hay to buy before | Hay to buy after | Saved | At $250 a ton |
|---|---|---|---|---|
| Small squares: ground to slat feeder (barn) | 4,312 lb | 3,854 lb | 458 lb | $57 |
| Round bale: no feeder to ring feeder (barn) | 5,991 lb | 4,541 lb | 1,450 lb | $181 |
| Round bale: ring to restrictive feeder (barn) | 4,541 lb | 4,236 lb | 305 lb | $38 |
| Storage: uncovered on the ground to barn (restrictive feeder) | 5,475 lb | 4,236 lb | 1,239 lb | $155 |
| Storage: net wrap on the ground to covered and raised (restrictive feeder) | 4,755 lb | 4,316 lb | 440 lb | $55 |
| Worst setup to best: round bale, no feeder, uncovered, to small squares in a slat feeder, barn | 7,743 lb | 3,854 lb | 3,889 lb | $486 |
The bottom row is not the sum of the rows above, because the changes overlap. It compares the two ends of the scale directly. The largest single step is putting any feeder around a round bale: in the Minnesota trial the horses with no feeder wasted 57% of the hay and still ate only 1.3% of body weight, against 2.0 to 2.4% from feeders.
Hay per day by body weight, and a year's order
Daily amounts at three rates, and the tons to buy for a full year at 2% with a hayrack (5%) and barn storage (6%). Tons are short tons of 2,000 lb.
| Horse weight | 1.5% a day | 2% a day | 2.5% a day | Year at 2% with waste |
|---|---|---|---|---|
| 500 lb (pony) | 7.5 lb | 10.0 lb | 12.5 lb | 2.03 tons |
| 700 lb | 10.5 lb | 14.0 lb | 17.5 lb | 2.84 tons |
| 900 lb | 13.5 lb | 18.0 lb | 22.5 lb | 3.66 tons |
| 1,000 lb | 15.0 lb | 20.0 lb | 25.0 lb | 4.06 tons |
| 1,100 lb | 16.5 lb | 22.0 lb | 27.5 lb | 4.47 tons |
| 1,200 lb | 18.0 lb | 24.0 lb | 30.0 lb | 4.87 tons |
| 1,500 lb | 22.5 lb | 30.0 lb | 37.5 lb | 6.09 tons |
| 1,800 lb (draft) | 27.0 lb | 36.0 lb | 45.0 lb | 7.31 tons |
The waste percentages behind the feeder list: small square feeders from the University of Minnesota trial by Grev and colleagues (1% slat, 3% basket, 5% hayrack, 13% on the ground), round bale feeders from the Minnesota study of nine commercial designs (5 to 11% for restrictive designs, the calculator uses 11%; 19% ring, cone and tombstone; 33% hay sleigh; 57% no feeder). Storage losses come from University of Tennessee work on round bales as summarized by the UGA Forage Extension Team: 6% in a barn, 8% covered on tires or pallets, 19% net wrapped on the ground, 29% covered on the ground, 37% uncovered on the ground.
What horse owners ask before the hay order
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