Horse Feed Calculator

This page works out what to feed. For what it costs, put your own hay and grain prices into the horse feed cost calculator, which uses the same intake table so the two agree on the ration.

Horse nutrition is based on body weight and workload. The foundation of any horse’s diet is forage (hay or pasture), which runs from half the ration for a horse in hard work up to all of it for one standing in a field. Grain and concentrates supplement energy needs for working horses but should not replace forage.

The Golden Rule: Total daily feed intake = 1.5% to 3.0% of body weight Minimum forage = 1.0% to 1.5% of body weight

For a 1,000 lb (454 kg) horse, this means 15–30 lbs (6.8–13.6 kg) of total feed per day, with at least 10–15 lbs (4.5–6.8 kg) coming from hay or pasture.

Feed Requirements by Activity Level:

Common Horse Weights:

Hay Types and Quality:

Protein, and why the hay column above matters more than the bag does:

Crude protein requirements move with life stage, not just with size. The National Research Council (NRC) 2007 tables put a horse at rest near 1.26 grams of crude protein per kilogram of body weight per day, work adds roughly 10 to 35% on top, late pregnancy sits around 1.8, and early lactation is close to 3.1, which is nearly two and a half times maintenance. A growing foal is in the same region.

That is the number to have in mind when you pick hay. A 1,100 lb mare in early lactation eating 20 lbs of timothy at 9% protein gets about 1.8 lbs of it, against a requirement nearer 3.4 lbs. Grass hay cannot close that on its own, which is exactly why alfalfa or a mixed bale is the standard recommendation for lactating and growing horses rather than a preference. Feed the same mare in maintenance and the same hay covers her comfortably.

The concentrate ceiling:

Two limits worth respecting, and the calculator checks both.
No more than about 0.5% of body weight of concentrate in a single meal, roughly 5 lbs for a 1,000 lb horse. A horse’s stomach is small and it does not handle a large starch load; the excess reaches the hindgut undigested and ferments there.
And keep total daily concentrate under about 1% of body weight. If the arithmetic on a hard-working horse pushes past that, the answer is better forage, alfalfa, or added fat, not more grain. Colic and laminitis both trace back to this more often than to anything else on the list of mistakes below.

Water Requirements: Water = 5–10 gallons (19–38 liters) per day Horses in hot weather or heavy work may drink 15–20 gallons (57–76 liters) per day. Always provide unlimited access to clean, fresh water. A dehydrated horse can colic within hours.

Salt and Minerals: Every horse needs salt, so provide a salt block or loose salt at all times. Most horses consume 1–2 ounces (28–57 g) of salt per day, and a horse sweating through hard work loses considerably more than one in a field. Additional mineral supplementation depends on local hay quality and soil conditions.

Feeding Schedule: Divide daily feed into at least 2 meals (ideally 3 or more). Horses are designed to eat small amounts continuously. Long gaps without forage (more than 4–6 hours) increase the risk of gastric ulcers and behavioral problems. Hay nets with small holes slow consumption and extend eating time.

Common Feeding Mistakes:

• Feeding too much grain and too little hay
• Changing feed suddenly (always transition over 7–10 days)
• Feeding immediately before or after heavy exercise
• Not providing enough water
• Ignoring body condition (too thin or too fat)

Body Condition Scoring (BCS): Use the Henneke 1–9 scale to assess your horse’s weight. A score of 5 is ideal. You should be able to feel the ribs with light pressure but not see them. Adjust feed amounts based on body condition, not just activity level.