Estimate round or square hay bale weight and dry matter, reverse-solve density, and plan herd feed quantities and trailer payload counts.

Geometry-based estimate using as-fed density. Weigh representative bales for purchasing, feeding and transport; this does not establish a safe trailer load or a nutritionally adequate ration.

Bale Weight Formula (Volume × Density)

The following formula is used to calculate the bale weight from bale volume and an assumed (or known) hay density.

BALEW = BL × BW × BH × ρ

Variables:

  • BALEW is the bale weight (lb), when using feet and lb/ft³
  • BL is the bale length (ft) 
  • BW is the bale width (ft) 
  • BH is the bale height (ft) 
  • ρ is the hay/bale density (lb/ft³)

For a rectangular bale, multiply length×width×height by the measured or assumed as-fed density. For a round cylinder, useπ×diameter²×bale width/4 for volume. The calculator requires your density;10.5lb/ft³ is the example assumption below, not a universal default. Use total mass including water for as-fed density. Wet-basis moisture partitions that mass into water and dry matter; dry-matter density is a different input basis. Weigh representative bales for decisions about feeding, purchasing and transport.

How to Calculate Bale Weight?

The following steps outline how to calculate the Bale Weight.

  1. First, determine the bale length (ft).
  2. Next, determine the bale width (ft). 
  3. Next, determine the bale height (ft). 
  4. Next, gather the formula from above: BALEW = BL * BW * BH * ρ.
  5. Finally, calculate the Bale Weight.
  6. After inserting the variables and calculating the result, check your answer with the calculator above. 

Example Problem:

Use the following variables as an example problem to test your knowledge.

bale length (ft) = 3

bale width (ft) = 4

bale height (ft) = 5

BALEW = BL * BW * BH * 10.5 =  ?

Solution (using ρ = 10.5 lb/ft³): BALEW = 3 × 4 × 5 × 10.5 = 630 lb.