Hay Bale Weight Calculator
Knowing your hay bale weights is essential for buying and selling hay, planning winter feed inventory, and calculating transport loads. Enter the bale type, your measured bale dimensions, estimated forage density, number of bales, and moisture content to calculate per-bale weight, dry matter per bale, and total load tonnage.
Hay bale weight calculation
Dry matter per bale (lb) = Bale weight x (1 - Moisture% / 100)
Total weight (lb) = Number of bales x Average bale weight
Total tons = Total weight / 2,000
Total cost ($) = Number of bales x Price per bale
Dry matter calculation removes the weight of water from the as-fed weight. Hay purchased on a dry matter basis allows fair comparison between bales of different moisture levels. A $50 bale at 15% moisture contains more DM than a $50 bale at 25% moisture.
Typical bale weight reference ranges
- Small square bale (14 x 18 x 36 in): 40 to 75 lb.
- Large round bale (5 ft x 6 ft): 900 to 1,500 lb.
- Large square bale (3 ft x 4 ft x 8 ft): 800 to 1,200 lb.
- Alfalfa bales are typically 10 to 20% heavier than grass hay bales of the same dimensions due to greater density.
Hay bale weight calculator: frequently asked questions
How much does a small square hay bale weigh?
A standard small square bale (14 x 18 x 36 inches) weighs approximately 40 to 75 pounds when baled at typical moisture content (15 to 20%). Alfalfa bales are denser and heavier than grass bales of the same size. Bale weight depends on forage type, moisture at baling, and baler tension setting.
How much does a large round bale weigh?
A standard large round bale (5 ft diameter x 6 ft wide) weighs approximately 1,000 to 1,500 pounds depending on forage type and moisture. Alfalfa round bales tend to weigh 1,200 to 1,500 lb; grass hay bales typically weigh 900 to 1,200 lb at standard moisture.
How do I calculate tons of hay in a field?
Count the number of bales and multiply by the average bale weight, then divide by 2,000 to convert pounds to tons. For example, 200 round bales at 1,200 lb each = 240,000 lb / 2,000 = 120 tons. This calculator automates this calculation for a specified number of bales.
What is the dry matter content of hay?
Hay dry matter content is 100% minus the moisture percentage. Properly stored hay has 12 to 18% moisture, giving 82 to 88% dry matter. Wet hay above 20% moisture at baling risks mold and heating. Hay purchased on a dry matter basis removes the variable of moisture content from the price comparison.
How many round bales does a cow need per winter?
A 1,200-lb cow consuming hay at 2% to 2.5% of body weight per day needs approximately 24 to 30 lb of dry matter per day. A 1,200-lb round bale at 85% DM provides about 1,020 lb DM. At 27 lb DM per day, one bale lasts approximately 38 days. For a 150-day winter, you need approximately 4 bales per cow.
Official sources
- University of Wisconsin Extension: Estimating Hay Bale Weight.
- USDA NRCS: Forage and Hay Management.
Reviewed by the CalculatorHub team, edited by James Graham, 14 June 2026. See our methodology.