Most healthy adult horses eat roughly 1.5–2.5% of their body weight in total feed every day — forage plus any grain which works out to about 15–25 lb of feed for a typical 1,000 lb horse (Kentucky Equine Research). This horse feed calculator turns that guideline into a daily hay-and-grain plan based on your horse’s weight and workload, then flags the two limits that keep the ration safe.
The number this feed calculator for horses uses
The engine is simple and forage-first. A horse’s total daily intake is set as a percentage of body weight that rises with work: idle horses sit near the bottom of the range and hard-working horses near the top. The Merck Veterinary Manual puts the usual maximum dry-matter intake at about 2–2.5% of body weight, with ponies and youngsters able to eat a little more. From that total, the calculator splits the ration into forage and concentrate and holds forage at half the diet or more, because University of Minnesota Extension advises that forage should make up at least 50% of the daily ration even for horses in hard work.
Two guardrails are built in. Forage never drops below 1% of body weight (the roughage floor that keeps the gut working), and grain in any single meal never tops 0.5% of body weight — about 5 lb for a 1,000 lb horse — to avoid overloading the hindgut with starch (University of Nebraska–Lincoln Extension). When the grain total climbs past that ceiling, the tool tells you how many feedings to split it into.
How much hay should I feed my horse per day?
For most horses, the answer is “more than you’d guess, and almost all of it hay.” When given free access, horses will happily eat 2–2.5% of their body weight in hay a day, and most should consume around 2% (University of Minnesota Extension). For a 1,000 lb horse that’s roughly 20 lb of hay daily; for a 1,200 lb horse, closer to 24 lb. An idle or lightly worked horse on good grass hay can often meet its entire energy requirement from forage alone no grain needed. Grain (concentrate) only enters the picture when forage can’t supply enough calories, typically for horses in moderate to heavy work, late-pregnant or lactating mares, hard keepers, or growing youngsters.
The typical range matters because biology varies. Easy keepers hold weight at the low end (or need restriction), while Thoroughbreds, hard keepers, and horses in heavy work may need the top of the range or slightly beyond. Always let body condition — not the number on a chart — have the final say, and weigh your hay rather than counting flakes, since flake weight varies wildly.
Horse feeding chart by workload and weight
These are practical starting points. Total intake is shown as a percentage of body weight, with a typical forage-to-concentrate split; adjust up or down to hold a healthy body condition score.
| Workload / class | Total daily feed (% of body weight) | Forage | Concentrate (grain) |
|---|---|---|---|
| Maintenance (idle / pasture pet) | 1.5–2.0% | 100% | 0% |
| Light work (1–3 hr/week) | 1.75–2.0% | ~90% | ~10% |
| Moderate work (3–5 hr/week) | 2.0–2.5% | ~70% | ~30% |
| Heavy work (4–5+ hr/week) | 2.25–2.75% | ~60% | ~40% |
Translated into pounds for common sizes (at about 2% of body weight):
| Body weight | Total daily feed (~2%) | Forage minimum (1%) | Max grain per meal (0.5%) |
|---|---|---|---|
| 800 lb (pony / small horse) | 16 lb | 8 lb | 4 lb |
| 1,000 lb (average riding horse) | 20 lb | 10 lb | 5 lb |
| 1,200 lb (large riding horse) | 24 lb | 12 lb | 6 lb |
| 1,400 lb (warmblood / draft cross) | 28 lb | 14 lb | 7 lb |
How to use the horse feed calculator by weight
Four quick steps:
- Enter your horse’s body weight in pounds or kilograms. If you don’t know it, open the “Estimate it with a tape” panel and enter heart girth and body length — the tool applies the standard adult-horse formula, (girth² × length) ÷ 330.
- Choose the workload class that best matches your horse’s real weekly exercise.
- Read the total daily feed figure, then the forage and concentrate amounts below it.
- Check the guardrails: keep hay above the 1%-of-bodyweight floor and split grain so no single meal exceeds 0.5% of body weight. Print or save the plan for your barn whiteboard.
BarnCalc · Horses
Horse Feed Calculator
Estimate daily hay & grain by your horse's weight and workload.
Unit
Don't know the weight? Estimate it with a tape
Adult-horse formula: (heart girth² × body length) ÷ 330. Measure girth around the barrel just behind the withers/elbow; length from point of shoulder to point of buttock. Fills the weight box above in lb.
Total daily feed
22.5 lb
≈ 2.25% of body weight (typical range 2.0–2.5%)
Forage / hay
Concentrate / grain
Grain feedings/day
Minimum forage: at least 10.0 lb (1% of body weight) — never go below this.
Max grain per meal: 5.0 lb (0.5% of body weight). Split larger amounts across more feedings.
Feeding rate chart — by workload & body weight
| Class | Total (% BW) | Forage | Concentrate |
|---|---|---|---|
| Maintenance (idle) | 1.5–2.0% | 100% | 0% |
| Light work | 1.75–2.0% | ~90% | ~10% |
| Moderate work | 2.0–2.5% | ~70% | ~30% |
| Heavy work | 2.25–2.75% | ~60% | ~40% |
| Body weight | Total ~2% | Forage min (1%) | Max grain/meal (0.5%) |
|---|---|---|---|
| 800 lb (pony/small) | 16 lb | 8 lb | 4 lb |
| 1,000 lb (light riding) | 20 lb | 10 lb | 5 lb |
| 1,200 lb (large riding) | 24 lb | 12 lb | 6 lb |
| 1,400 lb (warmblood/draft cross) | 28 lb | 14 lb | 7 lb |
How it works: Most healthy adult horses eat about 1.5–2.5% of their body weight in total feed (forage + grain) each day, forage-first. This tool applies a workload-based intake target and split, then flags the 1%-forage floor and 0.5%-per-meal grain ceiling.
Disclaimer: These are planning estimates, not veterinary advice. Every horse differs by age, metabolism, hay quality, and health. Feed by weight (not scoops), adjust to body condition, introduce changes over 7–10 days, and consult your vet or an equine nutritionist — especially for foals, pregnant/lactating mares, seniors, or metabolic/laminitic horses.
Sources:
- University of Minnesota Extension — Using hay in horse diets
- Merck Veterinary Manual — Nutritional Requirements of Horses
- Univ. of Nebraska–Lincoln Extension — Basics of Feeding Horses (G1781)
- Oklahoma State Univ. Extension — Rations for Horses
- Rutgers NJAES / UMN Extension — NSC guidance for metabolic horses
Frequently asked questions
How much grain should I feed my horse per day?
Only as much as forage can’t cover. Many horses need no grain at all. When they do, keep each meal at or below 0.5% of body weight (about 5 lb for a 1,000 lb horse) and split larger totals across two or more feedings to protect the hindgut (University of Nebraska–Lincoln Extension). If your horse needs less than the bag’s minimum feeding rate to hold weight, switch to a ration balancer instead of underfeeding a fortified grain.
Can I feed my horse hay only, with no grain?
Often, yes. Good-quality grass hay can meet the energy needs of an idle or lightly worked adult horse on its own (University of Minnesota Extension). Because hay is frequently low in certain vitamins and minerals, pair a forage-only diet with a low-calorie vitamin-mineral supplement or ration balancer.
How do I calculate NSC in horse feed?
NSC (non-structural carbohydrates) = starch + water-soluble sugars, taken from a feed tag or a forage analysis. For horses prone to laminitis or with metabolic conditions, aim to keep total-diet NSC below about 10–12% (Rutgers NJAES). Test your hay, choose low-NSC concentrates, and soak hay for 30–60 minutes if needed to lower sugars.
Is this the same as the Purina or EquiMed horse feed calculator?
It answers the same question — how much to feed by weight and workload — but works from published university-extension and veterinary intake guidelines rather than a single brand’s product line, so the output is hay-and-grain amounts by weight rather than bags of one specific feed.
How do I weigh my hay?
Put a flake in a hay net on a luggage or fish scale, or a bucket of grain on a kitchen scale. Flake weight varies a lot between bales, which is exactly why feeding by weight beats feeding by scoop or flake.
Should I change feed amounts suddenly?
No. Introduce any new hay, grain, or lush pasture gradually over 7–10 days, mixing old and new, to reduce the risk of colic or laminitis (University of Nebraska–Lincoln Extension).
Sources
- University of Minnesota Extension — Using hay in horse diets: extension.umn.edu/horse-nutrition/hay-horse-diets
- Merck Veterinary Manual — Nutritional Requirements of Horses and Other Equids: merckvetmanual.com
- University of Nebraska–Lincoln Extension — Basics of Feeding Horses (G1781): extensionpubs.unl.edu
- Oklahoma State University Extension — Rations for Horses: extension.okstate.edu
- Kentucky Equine Research — Feeding Horses: Don’t Miss the Forage for the Feed: ker.com
- Rutgers NJAES — Non-structural Carbohydrates and Equine Pastures (FS1340): njaes.rutgers.edu/fs1340
Reviewed for accuracy against University of Minnesota Extension, University of Nebraska–Lincoln Extension, Oklahoma State University Extension, the Merck Veterinary Manual, and Kentucky Equine Research.
Last updated: July 12, 2026.
Related BarnCalc tools: Visit the horse calculators hub, or try the horse weight calculator and the horse gestation calculator.