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FurCalc

Horse Feed Calculator — Daily Hay & Grain by Workload

How much hay and grain does your horse actually need per day? This calculator portions the daily ration by body weight and workload tier — maintenance, light work, moderate work, heavy work, or breeding/lactating mare — using the NRC Nutrient Requirements of Horses (6th edition) equations as the baseline. Forage should make up at least 1.5% of body weight to prevent ulcers and colic.

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Hard keepers maintain weight poorly; easy keepers founder on too much feed.

Daily feed
20lb / day
Forage (hay)
20 lb
Grain / concentrate
0 lb
Free-choice forage is ideal. Split grain into 2-3 meals of < 5 lb each to prevent colic.

Horse feed requirements by workload (1000 lb adult)

WorkloadHay / dayGrain / dayExamples
Maintenance (idle pasture)15-20 lb0-1 lb (ration balancer)Retired, pet
Light work15-20 lb1-3 lb1-3 hr/wk walk/trot
Moderate work17-22 lb3-6 lb3-5 hr/wk trail, lesson
Heavy work20-25 lb6-10 lbEventing, racing prep
Pregnant (last trimester)20-25 lb4-7 lb (mare/foal feed)From day 240
Lactating (peak month 2)22-30 lb8-12 lbEnergy needs ~2× maintenance

Forage minimum is 1.5% of body weight to prevent gastric ulcers and colic — never starve a horse below that floor.

Equine feeding terminology

Forage
Hay, pasture grass, haylage — fiber-based feed that should provide at least 1.5% of body weight daily.
Concentrate (grain)
Energy-dense feed (oats, sweet feed, pellets); split into 2-3 meals ≤ 5 lb each to prevent colic.
Ration balancer
Pelleted vitamin/mineral supplement fed in small amounts to easy keepers on forage-only diets.
DE (digestible energy)
Caloric measure used in horse nutrition; expressed as Mcal/day.

Frequently Asked Questions

How much hay does a horse eat per day?

1.5–2.5 % of body weight in forage. A 1,000 lb horse eats 15–25 lb of hay daily. Idle horses need 2 %; hard-working horses 2.5 % + grain.

How much grain should I feed my horse?

Depends on workload. Maintenance: often no grain needed. Light work: 0.5 lb per 100 lb body weight. Heavy work: 1.5 lb per 100 lb. Split into 2-3 meals of &lt; 5 lb each to prevent colic.

What is the best hay for horses?

Grass hay (timothy, orchard, brome) is the safest. Alfalfa is higher in protein and calcium — good for growing/working horses but excessive for idle adults. Always buy hay tested for nutrition and free of mold/dust.

How often should I feed my horse?

Free-choice forage is ideal — horses' stomachs produce acid continuously. Grain meals split into 2–3 per day. Never exceed 5 lb of concentrate per meal.

Should I soak hay for my horse?

Soak hay 30–60 minutes for horses with respiratory conditions (heaves), dental issues, or laminitis (to reduce sugar). Don't soak longer than 12 hours or nutrients leach.

Sources & References

  1. [1]
    NRC Nutrient Requirements of Horses — National Research Council
  2. [2]
  3. [3]

Common mistakes to avoid

  • All-grain no-hay diet — causes ulcers, colic. Forage (hay/pasture) is 1.5-2.5% of body weight daily minimum.
  • Large infrequent meals — horses are trickle-feeders. 2+ hay meals/day; grain split into 2-3 small portions.
  • Sudden feed changes — 7-14 day transition to any new feed or forage.

Pro tips

  • Weight tape weekly during condition change; monthly at maintenance.
  • Grain isn't necessary for easy keepers — many horses thrive on hay + ration balancer.
  • Feed at the same clock time daily; horses' GI rhythms are circadian.