Guide
How high can you stack gaylord boxes?
Two high in a heated warehouse is normal. One high on an unheated dock past a month is more likely. Here is the arithmetic.
You can stack gaylord boxes two high when the bottom box can carry the loaded box above it, with margin. In a heated warehouse a 3‑wall Grade B box with 500 lb in it can; on an unheated dock past a month it cannot. The answer depends on four things: the box's rated capacity, its grade, the place it stands and how long it stands there. Stack Check does this sum for you; this page shows it.
The sum, in five lines
- Start with the rating. The maker's figure if you know it; otherwise the low end of the range sellers cite for the wall count: 2‑wall 800 lb, 3‑wall 1,000, 4‑wall 1,500, 5‑wall 2,000.
- Let the bottom box carry up to its rating on top when it is new and dry. This is our planning figure, set to be conservative.
- Cut it for the grade, the place, the time and any overhang. The factors are in the table below.
- Weigh what sits on it: each box above adds its load plus 30 lb for the box itself.
- Count the boxes it can carry, up to three high.
| Factor | Setting | Share of strength kept |
|---|---|---|
| Grade | New | 100% |
| Grade | Grade A | 90% |
| Grade | Grade B | 75% |
| Grade | Grade C | 50% |
| Place | Heated warehouse | 100% |
| Place | Unheated dock | 65% |
| Place | Trailer | 60% |
| Place | Cooler | 55% |
| Place | Freezer | 60% |
| Place | Covered outdoors | 50% |
| Time under load | Up to a week | 100% |
| Time under load | Up to 30 days | 85% |
| Time under load | Up to 90 days | 70% |
| Time under load | Past 90 days | 55% |
| Overhang | Box hangs over the pallet | 80% |
The factors multiply. They are planning figures, set below the published derating: about half the strength lost at 90% relative humidity, and nearly 45% after 90 days in humid conditions.
Three worked examples
A 3-wall Grade B box, 500 lb, heated warehouse, 30 days
Rated capacity 1,000 lb. The factors multiply to 64%, so the bottom box is allowed 638 lb on top. 1 loaded box on top add 530 lb; the bottom box is allowed 638 lb. Result: two high.
The same box on an unheated dock for 90 days
Rated capacity 1,000 lb. The factors multiply to 34%, so the bottom box is allowed 341 lb on top. One more loaded box adds 530 lb on the bottom box, and the bottom box is allowed 341 lb. Result: do not stack. The next stronger wall count is 4‑wall.
A 5-wall Grade A box, 700 lb, heated warehouse, one week
Rated capacity 2,000 lb. The factors multiply to 90%, so the bottom box is allowed 1,800 lb on top. 2 loaded boxes on top add 1,460 lb; the bottom box is allowed 1,800 lb. Result: three high.
What the sum leaves out
- Pallet condition, forklift handling and a sloping dock floor all matter and none is in the sum.
- A damaged or crushed box is not a Grade B. Remove it from the stack.
- Cold boxes moved into a heated plant sweat. Let them reach room temperature before you stack or open them.
- Every result is labelled a conservative estimate, not a load rating. Check the maker's rating and your own safety rules.
Run your own numbers in Stack Check. For the reasons behind the factors, see box compression strength and cold docks; for what each wall count carries, weight capacity.
The habits behind a good stack
A stack height is only as good as the stack. Build it square, with boxes aligned corner to corner, on a flat floor, with the strongest box at the bottom. Do not mix sizes in a stack; a smaller box on a larger one leaves the overhang unsupported and takes strength from the box below. Check the bottom box first when you come to a stack that has stood for weeks. If its walls are bowed or its corners are rounded, unstack from the top.
When the answer is one high
One high is a perfectly good answer. It means the box in the place you have chosen is already doing as much as it should, and a second box on top would ask for more. The right response is to look at the place before you look at the box: a drier or warmer bay, a shorter wait or a stronger wall count can turn one high into two without any change in the load.
What to do when a stack has already leaned
Do not push it straight. Unload from the top, one box at a time, until you reach boxes that stand square, then rebuild with the best boxes at the bottom. Set aside any box with bowed walls or crushed corners; they are Grade C at best. Look at the floor under the stack, too, because a leaning stack often means a soft spot in the floor or a pallet with a broken board.
Racking is not stacking
Putting a pallet of gaylords on a steel rack is a different question, because the rack carries the weight and the box carries only itself. The answer depends on the rack's rating and on the pallet, and it is outside what Stack Check answers. Ask the rack's maker or a qualified engineer, and treat this guide as being about boxes standing on boxes.
Time is the factor people forget
A stack that holds for a day may fail in a month. Corrugated board creeps under steady load: the walls slowly bow and the box loses height long before it collapses. That is why the tool asks for the time as well as the weight, and why the humidity derating published for 90 days under load is much larger than the figure for a single day. If a stack has to stand for an uncertain time, plan for the longer period.
Floors and pallets
A stack is only as level as the floor under it. Check for soft spots, drains and sloping slabs, and replace any pallet with a broken board.
Strapping a stack together helps it ride but adds no strength.
Questions, answered
How high can you stack gaylord boxes?
Two high is common in a heated warehouse for a dry, mid-weight load. Past 30 days, on an unheated dock or in a cooler, most used boxes drop to one. Three high needs a strong wall count and a dry place.
Can gaylords be stacked outside?
Covered outdoors is the weakest place in our sum: humidity can pass 85%, where stacking strength often falls to about half.
Does it matter if a box overhangs the pallet?
Yes. Virginia Tech research found compression strength falls as overhang grows. We cut an overhanging box to 80%.
Sources and last reviewed
Facts on this page were last reviewed 2026-11-11.
- PaperIndex Academy: humidity and corrugated strength: How corrugated board loses compression strength as relative humidity climbs from 50% to 90%.
- AICC: strengthening corrugated against cold weather: Industry guidance on cold weather, condensation between temperature zones, and strength lost over 90 days under load.
- Virginia Tech: pallet overhang and box compression strength: University research on how pallet overhang lowers box compression strength.
- Container Exchanger: the gaylord box guide: A reseller's plain-language guide to gaylord sizes, walls, capacity ranges and bottoms.
- Uline: 46 x 38 x 36 triple wall octagon bulk bin: A maker's listing for the 46 x 38 x 36 octagon, with capacity, outside size and empty weight.