How this calculator works
Choose a hay allocation from an existing ration, or estimate the hay dry-matter allocation as a percentage of body weight. Enter only the hay portion, not total diet intake. Each group must have an allocation appropriate to its animal class and production stage. The calculator neither selects an allocation nor checks nutritional adequacy. There is no automatic grain subtraction or cold-weather multiplier.
Dry matter is the part of hay remaining after water is excluded. Use a forage analysis where available, identify whether the dry-matter value is measured or estimated, and weigh several representative bales. The allocation is multiplied by animal count and days. Dividing that seasonal dry matter by the entered hay dry-matter fraction gives the consumed hay equivalent.
Feeding loss is a share of hay offered; storage loss is a share of incoming hay. To work backwards to a purchase, divide the consumed equivalent by the fraction retained after feeding, then by the fraction retained after storage. Enter losses for your feeding arrangement, hay lot and storage period. A percentage from a different animal species, feeder design or storage duration is not automatically applicable.
Combine all groups before rounding up to whole bales. Purchase weight, price and space use that whole-bale count. The ledger reconciles consumed hay, feeding loss, storage loss and rounding surplus at the same entered dry matter. It does not predict moisture changes, selective nutrient loss or whether weathered hay remains suitable. Already-stored or mixed hay lots need separate assessment.
Compare the same required hay dry matter using each option’s entered dry matter, feeding loss, bale weight and quote. Cost per ton uses required hay dry matter as its denominator; equal dry matter does not mean equal energy, protein or feeding value.
Body-weight percentages depend on animal class and diet: Extension Horses distinguishes forage from the total ration; Nebraska Extension describes goat intake on a dry-matter basis. Mississippi State Extension explains the dependence of storage losses on conditions and duration. These sources support the distinctions above, not endorsement of every entered scenario. See About & sources for the full source record.
Compare quotes with the price converter, check the storage space, or build a cattle hay plan.
Frequently asked questions
Are round bales or square bales cheaper?
Either option can cost less. Compare whole-season purchase cost using the entered hay dry matter, losses, actual bale weights and quotes. Equal dry matter does not establish equal nutritional value.
How many square bales equal one round bale?
Divide the round bale’s actual weight by the square bale’s actual weight for a physical weight comparison. To compare usable hay, also account for each lot’s dry matter and feeding loss.
How should I enter feeding loss?
Enter a feeding-loss assumption appropriate to your animal class, bale and feeding arrangement. This calculator does not apply a universal no-feeder loss percentage.
Plan the rest of the barn
BaleMath is free to use. Numbers are planning estimates, not veterinary or nutritional advice.