How many hay bales fit in a 40 ft container?

Where the 400 comes from

A 40 ft gives you about 320 square feet of floor and roughly 2,390 cubic feet above it. Interior height on a standard box runs near 7 feet 10 inches and usable width is a little under 8 feet. Those three numbers are the whole calculation.

A common small square bale runs about 14 by 18 by 36 inches. Laid flat it covers roughly four and a half square feet, so a layer wall to wall lands near 67 bales. Six layers puts you at seven feet of hay with daylight left overhead, and six times 67 is a little over 400.

That is the ceiling, not a promise. Bales vary an inch in every direction, the last row against the far wall is always the worst one, and most people want a lane to walk. Take out a walkway and you are nearer 320 or 350.

Bale size is the biggest lever on the answer

Small squares are the only bale that gets near 400, because they are the only one small enough to pack tight. Every other shape wastes space, and the bigger the bale the more it wastes.

• Small squares, roughly 14 by 18 by 36 inches: about 400 stacked tight, closer to 320 with a walkway.
• Three by three by eight foot large squares: two across the width, four deep, two layers high, so roughly 16 bales.
• Four by four by eight foot large squares: one across most of the width and one layer high, so four or five.
• Four by five round bales: eight or nine standing in a single file down the length.

Notice what happens between the first line and the last. Same box, same cubic feet, and the count drops by a factor of forty. That is not the container changing. It is the geometry of the bale.

Round bales are a different problem entirely

A 4 by 5 round is five feet across. The interior is a little under eight feet wide, which is not room for two side by side and is far more than one needs. You lose the corners no matter how you turn them, and you cannot stack a second course of five foot rounds under a 7 foot 10 inch ceiling.

So a 40 ft holds a single row of eight or nine rounds and calls it a day. Getting them in is its own chore, since the floor sits on blocks and there is no dock to work off. If rounds are the bulk of your hay, the steel is the wrong tool for the hay and the right tool for everything else on the place.

Weight is not what stops you. Air is.

Four hundred small squares at 45 pounds apiece is around 18,000 pounds. A 40 ft is built to cross an ocean loaded, so neither the floor nor the corner posts are the limiting factor. Nothing about that load worries the box.

Moisture does. A sealed container is very good at keeping rain out and not naturally good at letting damp air leave. Hay that goes in a little green will heat, sweat and mold, and there is nowhere for that moisture to go except back into the stack. Put dry, cured hay in and give the box a way to breathe.

Vents cut high in the roof and low in the side wall let that damp air climb out instead of settling back into the stack. We cut and fit them in the shop before the box ships. Then set the box where you can back a wagon to the doors in February. A 40 ft comes in on a tilt-bed and wants around 95 feet of straight, firm approach to slide off level.