How this hay calculator works

This supply calculator scales a daily plan across a count of horses and days. Use an average only when that accurately represents the group; otherwise calculate groups separately. Waste is the fraction of purchased hay that never reaches the animal, so it belongs in the denominator. Bale weight matters more than a bale’s name or dimensions. Storage quality and a feeding plan remain separate from this inventory calculation.

A worked example

One 1,000-pound horse at two percent for 120 days consumes 2,400 lb. With ten-percent purchase losses, the order is 2,400 ÷ 0.9 = 2,666.67 lb. Dividing by a 50-pound bale and rounding up gives 54 whole bales. Two otherwise identical horses need 107 bales, after rounding the combined total.

Waste means a share of purchases

A ten-percent loss means ninety percent of what you buy reaches the animal. Divide the required intake by 0.9 rather than simply adding ten percent to it. That distinction becomes meaningful over a winter or across several horses. Waste here includes your chosen combined allowance for loss; the calculator does not independently estimate feeder performance, spoilage, or storage damage. Use a measured farm record where available.

Bale weight and practical rounding

Enter the bale’s actual average weight rather than relying on its dimensions or a generic label. Total mass is divided by that weight, then rounded up once to obtain a whole-bale purchase quantity. Rounding each horse or each day separately would produce a different and often inflated order. If weights vary considerably, retain a practical reserve and plan storage without treating the arithmetic as an inventory guarantee.

Keep nutrition separate from inventory

Hay mass alone does not establish digestible energy, protein, minerals, or suitability. The entered percentage and as-fed basis must agree with the feeding plan. Pasture and other feeds are not automatically included. Discuss hay analysis and individual requirements with an equine nutritionist, particularly for health restrictions or demanding workloads. Printed calculations should include the input percentage, days, animal count, bale weight, and waste so the order can be reproduced.

Sources and review status

The source links and editorial check date are shown beside this explanation. They identify the reference used for the calculation, not an endorsement of this site. No veterinarian has reviewed this implementation. A change in source evidence should lead to a new check of the equation, input choices, and example.

Hay Calculator