Currency changes notation only; entered amounts are not converted.
Horse hay planner
How much hay does your horse need?
Estimate the hay to purchase from an entered hay dry-matter allocation, hay dry matter, and separate feeding and storage losses. Review the assumptions for your animals before using the result.
The purchase estimate depends on the hay allocation you enter. Dry matter excludes water. BaleMath converts that allocation to incoming hay, accounts for losses and rounds the combined requirement up to whole bales.
Stock and loss weights assume the same bale weight and dry matter as the incoming lot. Mixed or already-weathered stock needs separate assessment. Ledger weights are equivalents at the entered dry matter, not measured moisture changes.
Total hay for the season
— bales
Total
—tons
Per head/day
—lb
Season
— days
Est. cost
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Cost/head/day
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Cost/head/season
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Storage
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What if my bales are lighter or heavier?
Your entered bale weight stays the headline plan. Open this only if you want to compare it with the sourced reference range for this bale type.
Scenario
Average bale
Bales required
Est. invoice
Rounding surplus
Coverage from headline order
Your entered weight
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Reference lighter bale
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Reference heavier bale
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This keeps the same hay need, feeding/storage losses, and price per bale. The reference range is planning context, not a guarantee of a seller's bale weight. Method & sources.
Continue your winter plan
Reuse compatible values from this result in the next calculator.
Your entered inventory already covers this gross hay plan, so there is no remaining purchase weight to compare.
One or more animal groups are not supported by the winter-water calculator, so no groups were transferred.
Print, copy, or share this plan
Copied plan links contain the values entered above and may appear in browser history or server logs. No tracking or URL shortener is used.
Compare two plans
Save two gross hay plans in this page's temporary memory and compare the result-driving assumptions and totals.
Compare two gross hay plans
Save the current gross seasonal hay requirement to Plan A or Plan B. This comparison is before hay already on hand and excludes the Check my season operational add-on. These snapshots are ephemeral: they stay only in this page's memory and disappear when the page reloads or closes. They are not added to copied links, summaries, or printouts.
Historical source example: this reproduces the cited approximation, not the current dry-matter inventory method.
Step
Formula
Engine result
Seasonal base
1 horse × 1,000 lb × 2.5% × 214 days
5,350 lb
Whole bales
5,350 lb ÷ 50 lb bales, rounded up. No added storage or feeding waste.
107 bales
Source: Nutrena/University of Minnesota, K. Martinson, “Estimating Winter Hay Needs”. See About & sources for the complete methodology and citation list.
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. Choose allocations appropriate to each group’s class and 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.
For an arithmetic example only, assume 10 animals at 100 lb, a 2% daily hay-DM allocation, 100 days, 90% hay DM, 10% feeding loss, 5% storage loss and 50 lb bales. Required DM is 2,000 lb; incoming hay is 2,599.09 lb; purchase is 52 bales or 2,600 lb. These are test assumptions, not feeding recommendations.
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.
Entering hay already on hand subtracts whole bales from the rounded gross requirement and shows the net bales and cost still to buy. Check my season fields turn entered mid-season stock into an observed disappearance rate, a projected run-out date, and a whole-bale reorder quantity. The storage-upgrade scenario uses entered targets for seasonal savings and simple payback; supplier lead time adds an order-by date. Use the price converter, water planner and manure planner. The round-vs-square calculator compares explicit hay-DM purchases.
Barn-space volume uses Missouri Extension planning rates of 250 ft³/ton square and 310 ft³/ton round (US short tons); Extension Horses corroborates the square-hay rate. Actual needs vary with bale density, dimensions, and stacking; ventilation, access aisles, equipment turning space, wall clearance, and local fire-code space are not included.
Enter an appropriate hay dry-matter allocation for your animal or group. Body-weight mode multiplies live weight by your entered hay-DM percentage; existing-ration mode uses the hay-DM amount you supply. Neither mode checks nutritional adequacy.
How many bales of hay does one horse need for winter?
Divide seasonal hay dry matter by hay DM fraction, then by the fractions retained after feeding and storage losses. Divide by bale weight and round the combined requirement up once.
Does feeding grain reduce how much hay a horse needs?
BaleMath does not automatically subtract grain or calculate a substitution ratio. Use the hay portion of an appropriate existing ration, and seek qualified advice when changing the diet.