How this calculator works
The main rule uses fresh manure per 1,000-pound animal unit. UMass Extension publishes 45 pounds per day for a horse, 60 pounds for a beef cow-calf unit, 106 pounds for a lactating dairy cow whose manure is handled as a solid, and 40 pounds for sheep. A University of Maryland Extension solid-manure worksheet uses 85 pounds per day for bred dairy heifers. Utah State University Extension publishes 4.2 pounds per day for an 80-pound goat and 8.4 pounds per day for a 160-pound goat; both rows support 52.5 pounds per day per 1,000 pounds. The calculator scales the rate by group weight and head count, then totals it across your collection days. The published sheep, heifer, and goat starting weights remain editable.
The easy-to-miss addition is bedding. The extension tables describe manure before bedding, and Utah State explicitly says its table contains only actual manure, but what leaves a stall or barn usually includes shavings, straw, or another absorbent material. The calculator keeps fresh manure and bedding separate, then adds your bedding percentage to show total waste weight. Its 5% starting value follows UMass's published example, but it is not a universal barn average. Manure deposited on pasture may not be collected at all, while heavily bedded stalls can add far more material than this default.
Use judgment before turning the tonnage into a storage design. Feed, water, animal class, bedding practice, rainfall, wash water, and handling all change the weight, moisture, and density of the pile. Weight alone cannot give volume. The optional measured-volume section follows the NRCS known-container method: subtract the empty-container weight from three filled weights, average those net samples, and divide by the known container volume to estimate bulk density. It then divides this plan's manure-and-bedding weight by that measured density. Its rectangular comparison uses only your usable length, width, and depth; it does not add design allowances. Measure actual waste when possible, allow for unavailable fields or routes, and ask local extension or conservation staff about setbacks, runoff control, freeboard, and construction. Nutrient content also varies, so land application should follow soil and manure testing. Pair this estimate with the same herd's winter feed plan and backup-water requirement. Entering actual payload capacity converts the period total into whole loads or trips, average loads per week, and unused capacity in the final load.
Manure weight method and the horse, beef cow-calf, lactating dairy cow, and sheep rates follow UMass Extension's “Manure Inventory.” The mature-sheep example follows University of Connecticut Extension's “Nutrient Management for Grazers”; the bred-heifer rate, starting weight, and worked result follow University of Maryland Extension's “Manure Management”; and the goat rate and 80-pound starting weight follow Utah State University Extension's “How Much Manure Will My Animals Produce?” Measured density follows USDA NRCS Agricultural Waste Management Field Handbook, chapter 13; the rectangular usable-volume comparison is corroborated by Montana State University Extension. Planning estimate only — confirm actual waste, storage requirements, and nutrient-management rules with local agricultural professionals.
Frequently asked questions
How much manure does a horse produce per day?
Using UMass Extension's planning table, a 1,000-pound horse produces about 45 pounds of fresh manure daily, before bedding is added.
How much manure does a cow produce per day?
A 1,000-pound beef cow-calf unit is estimated at 60 pounds daily. A 1,000-pound lactating dairy cow handled as solid manure is estimated at 106 pounds.
How much manure storage do I need?
The main result estimates weight. Three matching known-volume samples let the optional section estimate site-specific manure-and-bedding volume and compare it with entered rectangular usable space. It is not an engineered or regulatory storage design; still use local guidance.
Plan the rest of the barn
BaleMath is free to use. Numbers are planning estimates, not professional storage, engineering, or nutrient-management advice.