Horse Hay Calculator

The Horse Hay Calculator works out how much hay your horse needs each day from its body weight and activity level, expressed as a percentage of body weight. Horses are grazing animals built to eat forage almost continuously, so getting the daily hay amount right is one of the most important parts of keeping a horse healthy. This tool turns the standard "percentage of body weight" rule into a practical feeding plan — daily pounds or kilograms, the number of flakes and bales, how long a supply will last, and an estimated hay cost.

How Much Hay Does a Horse Need?

As a rule of thumb, a horse eats forage equal to about 1.5% to 3% of its body weight per day on an as-fed basis, with 2% being the classic guideline for a healthy adult horse at maintenance. The exact figure shifts with activity level: an easy keeper or a horse on a weight-loss program sits toward the lower end, while horses in heavy work, growing youngsters, and lactating mares need more. For a 1,100 lb (500 kg) horse at maintenance, 2% works out to about 22 lb (10 kg) of hay per day.

Horse Hay Formula

The core calculation is a single multiplication, and this tool then converts the result into flakes and bales.

"As-fed" means the hay is weighed as it is actually served, including its natural moisture. Grass hay is typically around 88–90% dry matter, so most simple feeding guidelines — including this calculator's default — work on an as-fed basis to keep things practical for owners.

Hay Requirement by Activity Level

Use the activity level that best matches your horse's typical week. The percentages below are forage targets as a share of body weight; horses in harder work usually receive concentrated feeds in addition to this forage base.

Why the Minimum Matters

Horses evolved to graze for many hours a day, and a steady flow of long-stem forage keeps the digestive tract moving. Feeding too little hay — generally below about 1.5% of body weight — raises the risk of gastric ulcers, colic, and stereotypic behaviours like cribbing. Even horses that need to lose weight should usually stay at or above this forage floor, ideally using lower-calorie hay and slow-feeder nets rather than simply cutting the amount. Always make diet changes gradually and check with your vet for horses with metabolic conditions.

What Affects How Much Hay Your Horse Needs?

How to Use This Calculator

1. Enter your horse's body weight: Choose imperial (lb) or metric (kg) and type the weight. A weight tape or livestock scale gives a more accurate figure than eyeballing.
2. Select the activity level: Pick the option that matches your horse's typical workload, from easy keeper to heavy performance work.
3. Add flake, bale, and cost details (optional): Enter the weight of one flake and one bale, plus your price per bale, to get flake counts, supply estimates, and cost figures.
4. Click Calculate: The tool shows the recommended daily hay amount, a healthy range, flakes per day, bales per day, week, and month, and the estimated cost.
5. Review the feeding plan: Check the suggested meal split and the step-by-step breakdown, then adjust to your horse's actual body condition over time.

Frequently Asked Questions

How much hay does a horse need per day?

A horse typically eats forage equal to about 1.5 to 3 percent of its body weight per day, with 2 percent being the common maintenance guideline. For a 1,100 lb horse at maintenance that is roughly 22 lb of hay per day. The exact amount depends on activity level, hay quality, and whether the horse also receives grain or pasture.

How do I calculate hay by body weight?

Multiply your horse's body weight by the forage percentage for its activity level and divide by 100. For example, 1,100 lb × 2 percent equals 22 lb of hay per day. This calculator does the math for you and also converts the amount into flakes and bales.

How many flakes of hay should I feed a horse?

It depends on how much each flake weighs, which varies a lot between bales. A typical grass-hay flake weighs about 3 to 5 lb. To find the number of flakes, divide the daily hay amount by the weight of one flake. Always weigh a few flakes rather than guessing, because flake size is inconsistent.

What is the minimum amount of hay for a horse?

To protect digestive health, horses should rarely receive less than about 1.5 percent of body weight in forage per day. Long-stem forage keeps the gut moving and reduces the risk of ulcers and colic, so even horses on a diet should not drop below this floor without veterinary guidance.

Does activity level change how much hay a horse needs?

Yes. Idle and easy-keeper horses are fed toward the lower end of the forage range, while horses in moderate to heavy work, growing horses, and lactating mares need more. Working horses usually receive higher-energy feeds alongside forage, but the forage base still rises with workload.

How much does it cost to feed a horse hay?

Cost depends on the price and weight of your bales and how much your horse eats. Enter your price per bale into the calculator and it will estimate the daily, monthly, and yearly hay cost based on the calculated ration. Hay prices vary widely by region and season.

Additional Resources

• Equine Nutrition - Wikipedia
• Hay - Wikipedia