In short
- Extension guidance: horses need at least 1% of body weight in forage daily, and most should eat about 2% in hay.
- With free access, horses will willingly eat 2 to 2.5% of body weight in hay.
- One 1,000 lb horse at 2% eats about 20 lb a day, around 7,300 lb a year before waste.
- Add waste: the calculator below adds it for you. Waste depends on how you feed.
On this page
This hay calculator for horses turns your herd size, body weight and bale size into daily hay, bales per week and month, how long your stock lasts and how many bales to buy for the season. It is free, runs in your browser and stores nothing. We are a referral service, not a feed supplier or a vet.
| Result | Amount |
|---|
The formula, plainly
- Hay eaten per day
horses x body weight (lb) x intake % = lb per day. Four 1,000 lb horses at 2% is 80 lb.
- Add waste
lb eaten / (1 minus waste %) = lb to feed. At 10% waste, 80 lb becomes about 88.9 lb.
- Convert to bales
lb to feed / bale weight = bales per day. Multiply by 7 for a week and 30 for a month.
- Season need and gap
Bales per day x feeding days = bales needed. Subtract the bales you have to get the shortfall. Days of stock = bales in storage / bales per day.
What the numbers look like with the defaults
These are example inputs, not recommendations. Your horses, hay and feeding method will differ.
How much forage do horses need?
| Level | Source says | 1,000 lb horse |
|---|---|---|
| Minimum roughage | At least 1% of body weight (UMN Extension) | 10 lb/day |
| Typical in hay | Most horses about 2% (UMN Extension) | 20 lb/day |
| Free access | 2 to 2.5% willingly eaten (UMN; Penn State) | 20 to 25 lb/day |
Also from UMN Extension: regardless of the class of horse, forages should make up at least 50% of the daily ration. Penn State describes hay and forage as the foundation of a horse's ration.
Where waste comes from
Penn State Extension reports hay waste that depends heavily on feeding method. Its figures for small square bales: about 13% with no feeder, 5% with a hay rack, 3% with a basket feeder and 1% with a slat feeder. For round bales it reports 57% with no feeder and 5 to 11% with restricted-access feeders. It also reports storage losses of 2 to 40%, depending on how bales are stored. If you feed on the ground or store outside, raise the waste input.
Not veterinary advice. Adjust for pasture, workload, pregnancy or lactation and age, and ask a vet or equine nutritionist what your horses should eat.
Pasture, Florida and bale storage
Pasture intake changes with the season, so the number of hay days is the input to adjust. We did not find extension pricing or local hay prices for Marion County and show none; ask local suppliers for current prices and bale weights. If you are planning where hay will live, see our guide to stall size and barn layout, which covers hay storage, and barn design for the Florida climate for ventilation and moisture.
Sources
- Using hay in horse diets, University of Minnesota Extension: 1% minimum, about 2%, 2 to 2.5% free access, forage at least 50% of the ration.
- Buying winter hay for horses, Penn State Extension: 2 to 2.5% of body weight, waste by feeder type, storage loss.
- Pasture and hay for horses, Penn State Extension: 1% roughage minimum (surfaced in our search; we did not open the full page).
The 10% waste default, 50 lb bale and 120-day season are our placeholders. We are a referral service for barn builders, not a hay supplier or veterinary provider.
Frequently asked questions
How much hay does a horse eat per day?
University of Minnesota Extension says horses need at least 1% of body weight in roughage daily, most should eat about 2% of body weight in hay, and horses with free access will willingly eat 2 to 2.5%. For a 1,000 lb horse, that is 10 lb at the minimum, about 20 lb typical, and 20 to 25 lb free-choice.
Why add a waste percentage?
Some hay is trampled, soiled or left uneaten. Penn State Extension reports waste varying widely with how hay is fed, for example 13% for small square bales with no feeder and 1 to 5% with a rack or slat feeder. The calculator uses 10% as an editable starting point of our own, not a measured figure for your barn.
How much does a bale of hay weigh?
It varies by bale type, hay and moisture. Small square bales are often in the range of 40 to 60 lb, but weigh a few from your own supply with a hanging or bathroom scale and enter the average. The default of 50 lb is our placeholder, not a standard.
Does this account for pasture?
No. If horses graze, they eat less hay. Enter a lower intake percentage for the share of the diet that hay covers, or shorten the feeding days to the weeks when pasture is not enough. Ask your vet or an equine nutritionist how much to adjust.
Is this veterinary advice?
No. It is planning arithmetic for ordering hay. Needs change with pasture, workload, pregnancy or lactation, and age. Ask a vet or equine nutritionist what your horses should eat.