Choosing cartonisation rules for different products

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Choose cartonisation rules by combining each SKU’s dimensions and weight with its packing constraints and the limits of available cartons. Start with the product type, then decide whether it needs cushioning, a particular orientation, temperature control or separation from other items. In Australia, box dimensions are measured in millimetres (mm), and carrier rules are based on centimetres and kilograms (theboxman.com.au).

Set the packing priority first: choose the smallest safe container, maximise fill, use the fewest cartons or minimise cost. These aims can conflict, so assess each rule for fit, protection, carton availability and carrier rating constraints. A picker who defaults to a familiar box can leave unnecessary empty space and inflate dimensional weight; oversized cartons inflate dimensional weight even when the contents are light (premiumpackaging.com.au).

Classify product constraints and set carton rules

Record each sellable unit’s length, width, height, weight, quantity, shape and material. Add whether it can be stacked or rotated, whether it is fragile or hazardous, and whether it needs a particular temperature or must travel separately.

For every stocked carton or mailer, record its internal dimensions, supported maximum weight, package type and restrictions. A carton must fit its items, accommodate required protection, support their combined weight and respect the Box restrictions configured in your cartonisation engine (techSHIP Support). Keep the range tight: matching stock sizes to your top three or four product shapes often delivers most of the benefit without bespoke runs (premiumpackaging.com.au).

For fragile items such as glass, require suitable cushioning, typically 20 to 40 mm on each side (premiumpackaging.com.au). Some cartonisation tools can apply additional constraints for sensitive or fragile products, such as 'this side up' information (optioryx.com). Use a custom SKU rule where needed, and do not select a carton that cannot accommodate the required protection.

Define compatibility rules to keep hazardous or allergenic items apart where required. Record each SKU’s hazard class with its safety data sheet link, its allergen flags and its temperature range (sgsystemsglobal.com).

Match the rule type to the product’s shape. Some engines can incorporate 3D spatial optimisation and item rules such as fragility or hazmat (paccurate.io).

For garments and other soft goods, use their dimensions, weight and material to assess fit against available cartons or mailers; do not assume that one package type suits every item. For a single SKU, match its dimensions to an appropriately sized carton; for mixed orders, assess the combined items and split them across cartons when one carton cannot meet the fit or handling rules.

Turn each constraint into a rule the engine can test. Simple category rules work for stable ranges, such as sending all items in product category X to Box 3 (paccurate.io). For more complex orders, the engine needs item dimensions, weights, item rules and available box options to evaluate (paccurate.io). Allow only packages that fit both the item and its cushioning, and reject any candidate that cannot support the combined weight (techSHIP Support).

In techSHIP, Handling Groups restrict which items can share a Package alongside physical fit, Box configuration and compatibility rules; items from different Handling Groups share a Package only when their effective compatibility permits it (techSHIP Support). Compatibility is an additional packing constraint on top of the physical rules, not a replacement for them.

Some engines can consider carrier rates, DIM divisors and surcharge thresholds; use the settings for your services rather than a universal formula (paccurate.io). Australian carriers, including Australia Post, Aramex, Toll and StarTrack, charge by whichever is greater, actual weight or cubic weight (theboxman.com.au). The divisor is not universal: some carriers use 5,000 rather than 4,000 for certain account types or service levels (theboxman.com.au).

Check each rule against the carrier’s own limits. One courier comparison site lists Australia Post’s maximum as 20 kg and 1.05 m for any dimension per parcel (parcel2courier.co.nz). A dense item that fits inside a flat-rate box and weighs 5 kg or under is charged a flat postage rate regardless of destination (theboxman.com.au).

Test awkward baskets

Test one small item, several identical items, a fragile mixed basket and a bundle with odd dimensions. Compare the carton and packing instructions with what an experienced packer would safely use.

Work the rule once by hand before you configure it. Measure the product’s longest, second-longest and shortest dimensions, add 20 to 40 mm on each side where the item is fragile, and match the total to a stock carton’s internal dimensions, not its external ones (premiumpackaging.com.au). Then check the combined weight against the box’s supported maximum.

Record why a packer overrides a rule, such as a protective insert being required. Use those cases to refine the product, compatibility and carton rules.

After launch, track the percentage of empty space in cartons and the percentage of orders where packers use the system-prescribed box (packchain.io). A rule that saves space but repeatedly causes damage or extra packing work is not an operational improvement.