Automatic packing by size
Enter a product's packed size and let Parcello choose boxes from your box library instead of writing box rules.
Available on the Operations plan and higher. Compare plans
Updated October 13, 2026
With automatic packing you don’t assign boxes to a product. You enter the size of one packed unit, and Parcello picks boxes from your box library for each order, fitting units by their dimensions. It suits catalogs with many products in a handful of box sizes.
Box rules stay the default. Nothing changes until you switch a product to automatic.
Before you start
- Add your boxes on the Boxes page. See Boxes.
- Know the size of one unit as it goes into a box, in inches, and its weight.
Set up your boxes
Open each box on the Boxes page. Under Automatic packing:
| Field | What it does |
|---|---|
| Use for automatic packing | On by default. Untick a box automatic packing should never choose. |
| Inside length, Inside width, Inside height | The space inside the box. Blank inside sizes use the outside size minus 0.5 in. |
| Box cost | What one box costs you. Parcello uses it to compare packing options. |
Automatic packing also reads Max weight in the box’s Limits group: the most the box may weigh with its contents. Blank means 150 lbs. The same limit caps box rules on every plan. See Box limits.
Only boxes with Status set to Active are used. Boxes larger than parcel carriers take (longer than 108 in, or more than 165 in length plus girth) are left out.
The Automatic packing column on the Boxes page shows each box’s setting.
Switch a product to automatic
- Go to Products, on the Box configuration tab, and find the variant.
- In the Packing column, change My box rules to Automatic.
- Enter the packed size of one unit in the three fields (length, width, height, in inches). Until all three are filled, the cell says “Enter the packed size”.
- Set the options you need (below).
Each change saves on its own.
The variant’s box columns stay as they are. Their content weights, added together, are used as the weight of one unit. Without them Parcello uses the Shopify weight. Switching back to My box rules brings the box rules back unchanged.
Options
| Option | What it does |
|---|---|
| Keep upright | Parcello may only turn the unit around, never tip it over. Enter as the height the side that must stay up. |
| Already boxed, can ship as is | The unit has its own shipping carton. It can ship alone in it, or go inside a bigger box with other units. |
| Max per box | The most units of this variant in one box, whatever else fits. Blank means no limit. |
How Parcello picks boxes
For each shipment, Parcello takes every unit on automatic packing, largest first, and tries several ways to place them: a new box sized to each unit, the same box type for all units, units already boxed shipped as they are, and one box per unit. Units are turned to fit (only around, with Keep upright). After placing, each box shrinks to the smallest box its contents fit.
From those options Parcello keeps the cheapest by an estimate that counts billable weight (the greater of actual and dimensional weight), each extra package, your Box cost, and a penalty for boxes large or heavy enough to draw an additional handling charge. The estimate only ranks the options. It isn’t a carrier price.
A box never weighs more than its Max weight or 150 lbs, whichever is lower, and is never over 108 in long, or over 165 in length plus girth. A unit that fits no box ships in its own packaging at its own size.
An example with three boxes in the library (10×8×6, 14×12×8 and 20×16×12 in) and a mug packed at 4×4×5 in, 2 lb:
| Ordered | Boxes |
|---|---|
| 1 mug | one 10×8×6 |
| 4 mugs | one 14×12×8 |
| 8 mugs | one 14×12×8 with 6, one 10×8×6 with 2 |
| 6 mugs, Max per box 2 | three 10×8×6 |
| 1 lamp packed at 24×6×6 | its own packaging (no box is long enough) |
Different products in one box
When Combine different products into shared boxes is on (Products > Box sharing), different products on automatic packing can share a box. When it’s off, each product packs on its own; two order lines of the same variant still share. See Shared boxes and ride-along items.
Products on automatic packing never share a box with products on box rules, and never host or ride along. Their boxes come after the box-rule boxes on the order.
Above 60 units in one shipment, each product packs separately so large orders stay quick.
Test a cart
The Test a cart card at the bottom of the Box configuration tab shows the boxes an order would ship in. Nothing is saved.
- Pick a Product and a Quantity. Use Add product for more lines.
- Leave Ship from on Each product’s location, or pick one location for all lines.
- Click Pack.
Each location and carrier gets its own list: every box with its size, how full it is, its weight and its billable weight, and what’s inside. A unit with no box shows as Own packaging. Products with neither box rules nor a packed size are listed as not packed. A box whose single unit is heavier than the box’s Max weight shows the note “Over this box’s N lbs limit. It can’t be split further, so it ships alone.” under it.
The card packs with the same rules as orders and checkout, box rules included, so you can test any product that has a ship-from location.
Find products without a size
The Packing filter on the Products page has My box rules, Automatic and Automatic, no size. When any automatic variant has no packed size, a line above the table says so, with a Show them link. Those variants pack by their box rules until you add the size.
Notes and limits
- Placement isn’t perfect: a mixed cart can use one more box than an ideal packer would.
- Automatic packing doesn’t use the Multiple Boxes (Meaning), Max qty per box or ride-along settings of the variant’s box columns.
- A product goes to freight when its carrier is Estes or FedEx Freight, or when one packed unit is too large or heavy for parcel carriers. See Freight with Estes.
- Live rates at checkout pack the cart with the same rules. See How checkout prices a cart.
- You can set the packing method and size from a spreadsheet. See Import and export product settings.
If you leave the Operations plan
Automatic can’t be chosen on other plans (“Automatic is available on the Operations plan.”). Variants already on it keep working in a simpler way: “Without the Operations plan, each unit ships in the smallest box that fits.” A variant with no packed size, or no box that fits, packs by its box rules. You can switch any variant back to My box rules.
Troubleshooting
A size field shows “0.1–999” and the change isn’t saved. Each side of the packed size must be between 0.1 and 999 inches. Max per box shows “1–999” when it isn’t a whole number in that range.
A unit ships in its own packaging when you expected a box. No active box with Use for automatic packing on holds it, by inside size or by Max weight (in the box’s Limits group). Check the inside sizes, or untick Keep upright if the unit may lie down.
The order didn’t change after you switched the product. Orders already packed keep their boxes. Use Recalculate Packages on the order (only offered while no shipment on the order has a label).