Softonic

Hay Calculator

Step 1 / 4 Animal type and units

Choose the animal type and units

Animal examples provide a planning starting point only. Keep the intake rate visible and change it for life stage, production, forage quality, health and local conditions.

The example rate is not a ration recommendation. Review and edit the dry-matter intake percentage before relying on the plan.

Weight units

Metric uses kilograms; imperial uses pounds. Avoid an unlabeled “ton,” which differs by market.

Use animals with a similar weight and feeding plan; calculate unlike groups separately.

Estimate how much hay to stage or buy for a herd, flock or group over a defined feeding period. The calculator starts with a planned hay dry-matter intake, then converts it to as-fed weight using the hay’s moisture, accounts for expected waste and divides by a measured average bale weight. It is an inventory planner, not a complete ration, forage-quality test or veterinary feeding recommendation.

How to plan hay and bale requirements

  1. 1

    Describe the animals

    Enter the number of animals and their average current body weight. Use separate calculations when classes or weights differ materially.

  2. 2

    Set the hay dry-matter plan

    Choose an editable planning starting point or enter the percentage of body weight that hay: not the whole diet: must provide as dry matter each day.

  3. 3

    Describe the hay and losses

    Enter feeding days, hay moisture, expected waste and an average as-fed bale weight. The calculator reports daily and period totals plus whole bales.

Hay inventory formula

Feed requirements are compared on a dry-matter (DM) basis because water adds bale weight without adding the same amount of feed nutrients. Let:

  • DM fraction = (100 − moisture %) ÷ 100
  • retained fraction = (100 − waste %) ÷ 100
  • daily hay DM = animal count × average body weight × hay DM % ÷ 100
  • daily as-fed hay to offer = daily hay DM ÷ (DM fraction × retained fraction)
  • usable DM per bale = as-fed bale weight × DM fraction × retained fraction
  • whole bales = round up(period hay DM ÷ usable DM per bale)
Quantity What it means Includes water? Includes planned waste?
Hay DM target Hay the animals are planned to consume, with water removed No No
As-fed hay to offer Physical hay weight to stage or feed Yes Yes
Bale weight Average weight of the bale as purchased or fed Yes Not yet
Usable DM per bale Dry matter left after the entered loss No Yes

Waste is handled by dividing by the retained fraction. With 20% waste, only 80% remains, so the required offered weight is target ÷ 0.80, 25% more, not merely 20% more.

Worked metric example

For 25 growing goats averaging 50 kg, a user-selected hay plan of 2.75% of body weight as DM, 90 days, hay at 15% moisture, 20% waste and 20 kg bales gives:

  • Daily hay DM: 25 × 50 × 0.0275 = 34.375 kg
  • Period hay DM: 34.375 × 90 = 3,093.75 kg
  • Usable DM per bale: 20 × 0.85 × 0.80 = 13.6 kg
  • Daily as-fed hay to offer: 34.375 ÷ (0.85 × 0.80) = 50.55 kg
  • Exact bales: 3,093.75 ÷ 13.6 = 227.48
  • Inventory to plan: 228 whole bales

The 2.75% value is only an editable planning example for growing small ruminants. It is not suitable by default for breeding or lactating stock.

Measure bales instead of guessing

Bales of the same nominal size can vary greatly with forage type, density and moisture. Weigh several representative bales and average them. If hay was bought by total weight, divide the delivered as-fed weight by the number of bales. Do not infer bale weight from dimensions alone when purchasing inventory.

The USDA dry-matter guidance uses body weight and a class-specific DM percentage, treats dry hay as roughly 90% DM when no test is available, and recommends actual forage analysis where possible. SDSU Extension’s 2026 forage inventory guidance likewise combines livestock class and weight, forage inventory and a waste estimate matched to the feeding system.

Planning is not ration balancing

Hay weight alone cannot prove that energy, protein, fibre, vitamins or minerals are adequate. Pregnancy, lactation, growth, heavy work, cold stress, illness, dental problems, pasture, concentrates and hay quality can materially change intake. Monitor body condition, refusals and actual use; test the forage and involve a veterinarian, extension specialist or qualified livestock nutritionist when setting a ration.

Moisture is arithmetic here, not a safety certificate. Never feed moldy or spoiled forage. High-moisture baleage requires correct fermentation and storage, and horses need particular caution because poorly preserved forage can create botulism risk.

Sources and product guidance reviewed 16 July 2026.

Frequently Asked Questions

It is the planned hay portion expressed as dry matter per day. If pasture, grain, silage or another forage supplies part of the diet, enter only the hay dry-matter percentage established for your plan. The calculator does not automatically subtract an assumed pasture contribution.

Dry matter is the feed remaining after water is removed. As-fed weight is the physical hay placed in the feeder, including its moisture. Ten kilograms of hay at 90% dry matter contains 9 kg of dry matter.

A 20% loss means animals receive only 80% of the offered hay. To deliver a fixed consumed target, the calculator divides by 0.80. Multiplying the target by 1.20 would still leave it short after 20% of that larger amount was lost.

Weigh several representative bales as-fed and use their average. Alternatively, divide the total delivered or purchased weight by the bale count. Bale dimensions alone do not reliably determine weight because density, crop and moisture vary.

No. They are editable planning starting points for the narrowly named class. Production stage, forage quality, climate, workload and the rest of the diet can change requirements substantially. Pregnancy, lactation, rapid growth, illness or performance work need a class-specific ration.

No. It calculates weight and inventory only. A forage analysis is needed to assess energy, protein, fibre and mineral content, and the complete ration must be compared with the needs of the animal class.

It can perform the dry-matter conversion, but it cannot verify fermentation, pH, wrapping, storage or safety. High-moisture forage varies widely and may carry mold or botulism risks if poorly preserved. Use a forage test and species-appropriate professional guidance, especially for horses.

Use records from your own storage and feeding system where possible. Waste can include weather damage, spoilage, trampling, sorting and feeder loss. Extension trials show that feeder design and management can move losses from low single digits to 20% or more, so review actual refusals rather than treating a preset as fixed.

No file or farm profile is uploaded. In the single-page calculator, the entered values are sent to this first-party application through Livewire to update the result. In funnel mode, values remain in the browser while you type and enter the page URL and browser history when you advance, so treat a copied URL as shareable.

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