Horse Feed & Weight Calculator

The most widely used method is the heart-girth and body-length formula. Measure the heart girth in inches all the way around the barrel just behind the withers and elbow, and the body length from the point of the shoulder to the point of the buttock. Then apply: weight in pounds equals girth squared times length, divided by 330. It is an estimate, but it is far more accurate than eyeballing and is the formula this calculator uses for adult horses.

As a rule of thumb, horses should eat 1.5 to 2 percent of their body weight in forage each day, measured as dry hay. For a 1,000 lb horse that is roughly 15 to 20 lbs of hay daily. Forage should be the foundation of every horse's diet. Most healthy horses do well around 2 percent, while easy keepers or metabolic horses may be held closer to 1.5 percent under veterinary guidance.

Senior horses still need the same forage-first foundation, but how they get it often changes. A horse with worn or missing teeth may struggle with long-stem hay and quid it onto the floor, so soaked hay pellets, chopped forage, or a complete senior feed can replace some or all of the hay. The total amount, around 1.5 to 2 percent of body weight, stays similar, but the form becomes softer and easier to chew.

Hard keepers that are losing topline often need more calories than forage alone provides, especially as teeth wear down. Keep forage at the top of the range, then add a senior feed and a source of fat or higher-calorie concentrate to close the gap. Always rule out underlying causes first, such as PPID, dental disease, ulcers, or parasites, with your vet before simply increasing feed, since weight loss in an older horse is often a medical signal.

The heart-girth and body-length formula is calibrated for average adult horses and is most accurate in that range. It tends to be less accurate for minis, very small ponies, and heavy drafts, and it is not intended for foals or pregnant mares. For those animals, use it only as a rough guide and ask your vet, who can also help you weight-tape and body-condition score for a fuller picture.

Accurate weight drives almost everything: correct medication and dewormer doses, the right amount of feed and supplements, and early detection of the slow weight loss that signals trouble in seniors. Because horses are stoic and changes happen gradually, a number you can track over time is far more reliable than a glance. Measuring monthly and logging it is one of the most useful habits in senior horse care.

Weight tells you how many pounds your horse carries, while the Henneke body condition score (a 1 to 9 scale) tells you how that weight is distributed as fat and muscle. A horse can hit a target weight while losing topline muscle and gaining fat, which is common with PPID and aging. Use weight and body condition together: weight for dosing and feed math, and condition scoring to judge whether your senior horse is truly in good shape.