Limit items per box, alternative boxes and carton packs
Put several units in one box, pick a box size by quantity, and pack carton multipacks so the order ships in the fewest sensible boxes.
Updated October 13, 2026
By default every unit of a product gets its own box. These settings on the Products page let you put several units in a box, choose between box sizes by quantity, and pack products sold as packs of cartons.
All of them are on the Box configuration tab, in the product’s row.
Max qty per box
Each box column has a Max qty per box field. Set it to the number of units that fit in one of those boxes (1 to 999). Blank means 1.
Parcello fills a box up to that number, then opens the next one. Mugs with a limit of 2:
| Mugs ordered | Boxes |
|---|---|
| 1 | 1 box with 1 mug |
| 2 | 1 box with 2 mugs |
| 5 | 3 boxes: 2, 2 and 1 |
The weight you enter in the box column is the weight of one unit. A box with two mugs weighs two mugs plus the empty box, and a part-filled box weighs only what’s in it.
On a product that ships in several parts (Unit split across boxes), each box column has its own limit. See Ship one product in several boxes.
When the box has a weight limit
A box can also have a Max weight (box and contents) on the Boxes page. Parcello then closes a box at whichever comes first, Max qty per box or the weight limit. With heavy units, a box can hold fewer than its Max qty per box. See Box limits.
When one unit and the empty box already weigh more than the limit, the box column on the Products page warns: “One unit and the box weigh more than this box’s N lbs limit.” That unit still ships, alone in the box.
Alternative boxes
Use this when a product can go in different box sizes depending on how many are ordered, for example a small carton that holds one and a large carton that holds two.
- Put each size in its own box column (Box 1, Box 2 and so on) with its content weight per unit.
- Set Max qty per box on each one.
- In the Multiple Boxes (Meaning) column, choose Alternative boxes.
Parcello packs with the box that has the largest Max qty per box (the first one listed if two tie). If the last box isn’t full, it moves down to the smallest box that still holds what’s in it. The number of boxes never changes: a part-filled box only gets smaller, it is never split.
With a small carton for 1 and a large carton for 2:
| Ordered | Boxes |
|---|---|
| 1 | small |
| 2 | large |
| 3 | large and small |
| 4 | 2 large |
| 5 | 2 large and small |
Parcello never moves a box down to one that is physically bigger than the main box. When the boxes have a Max weight, each box holds no more than the most any of the sizes can hold within its own limit, and a box moves down only to a size whose own limit holds its contents.
Carton packs
Some products are sold as packs of identical cartons, for example 4-packs, 8-packs and 12-packs of the same drink, shipped in mailers that hold one, two or three cartons. Set the mailers up as Alternative boxes on each pack variant, with Max qty per box counted in cartons (1, 2 and 3), then use the settings below.
Cartons per unit
On a variant set to Alternative boxes, the Multiple Boxes (Meaning) column shows Cartons per unit (1 to 99). Set it to how many cartons one unit is: 1 for a 4-pack, 2 for an 8-pack, 3 for a 12-pack.
When it’s above 1, the Max qty per box values on that variant are read in cartons. Enter the content weight of one whole pack in each box column. When a pack is split, each carton carries its share.
May ship in separate boxes
When Cartons per unit is above 1, a May ship in separate boxes checkbox appears. Leave it off and a pack always stays in one box. Tick it and its cartons can be spread over several boxes.
Three 8-packs (2 cartons each) with mailers for 1, 2 and 3 cartons:
| May ship in separate boxes | Boxes |
|---|---|
| Off | 3 two-carton mailers (2 + 2 + 2) |
| On | 2 three-carton mailers (3 + 3) |
Only when nothing else fits
Each box column of an Alternative boxes variant has an Only when nothing else fits checkbox. Tick it on a box you’d rather not use, usually the single-carton mailer. Parcello then rebalances cartons between the other boxes so that box is used only when nothing can be moved to avoid it.
Without it, the largest box fills first and the leftover goes in the smallest box that holds it. Single cartons with mailers for 1, 2 and 3:
| Cartons | Nothing ticked | Only when nothing else fits on the 1-carton mailer |
|---|---|---|
| 1 | 1 | 1 |
| 2 | 2 | 2 |
| 3 | 3 | 3 |
| 4 | 3 + 1 | 2 + 2 |
| 5 | 3 + 2 | 3 + 2 |
| 6 | 3 + 3 | 3 + 3 |
| 7 | 3 + 3 + 1 | 3 + 2 + 2 |
| 8 | 3 + 3 + 2 | 3 + 3 + 2 |
The 2 + 2 split for four cartons happens only because the 1-carton mailer is marked. A single carton on its own still ships in the 1-carton mailer, since there is nothing to rebalance.
Mixing pack sizes
Different pack sizes of one family (a 4-pack and an 8-pack using the same mailers) share mailers only when Combine different products into shared boxes is on. With it on, one 8-pack and one 4-pack go together in a three-carton mailer. With it off, each variant packs on its own: a two-carton mailer for the 8-pack and a one-carton mailer for the 4-pack. See Shared boxes and ride-along items.
When several variants share a mailer, Parcello uses the smallest Max qty per box any of them gives that mailer, so keep the values consistent.
Carton packs and weight limits
When a mailer has a Max weight, Parcello opens the mailer that holds the most cartons within its limit, and moves cartons between mailers only when the limits allow it. With a weight limit, carton packs can use more mailers than the fewest possible. For a pack that may ship in separate boxes, the weight warning on the Products page is for one carton: “One carton and the box weigh more than this box’s N lbs limit.”
Notes and limits
- These are counts you declare. Parcello doesn’t check whether the units physically fit by size. The box’s Max weight, when set, is the one check by weight. For size-based packing, see Automatic packing by size (Operations plan).
- Alternative boxes has no effect until the variant has a second box column. Cartons per unit, May ship in separate boxes and Only when nothing else fits only show on Alternative boxes variants.
- Live rates at checkout pack the cart with the same rules, so the quote and the label start from the same boxes.
- You can set all of these from a spreadsheet. See Import and export product settings.
- Orders already packed keep their boxes when you change a setting. Use Recalculate Packages on the order to repack it (only offered while no shipment on the order has a label).
Troubleshooting
Four cartons ship as 3 + 1 and you want 2 + 2. Tick Only when nothing else fits on the one-carton box.
An 8-pack and a 4-pack ship in two mailers. Combine different products into shared boxes is off. Turn it on in the Box sharing tab.
A box holds fewer units than its Max qty per box. The box reached its Max weight first. Check the limit on the Boxes page and the content weight in the box column.
A part-filled box didn’t move to a smaller size. Check that Alternative boxes is selected, that the smaller box has a Max qty per box that holds the leftover, that its Max weight holds the contents, and that it isn’t bigger than the main box. When the box is shared with another product, every product in it needs that smaller box in its own setup.