How to Size a PE Carton Liner for a Corrugated Box

Measure the inside of the erected carton and check liner fit with the actual contents before approving a production size.

Blown-film production at Hengyi. Liner fit is checked in the actual carton.

Start with the usable carton interior

Measure inside a fully erected carton. Record the internal length, width and height, and note inserts, pads or dividers that reduce the usable space. Add the maximum fill height and describe whether the liner is folded over, tied or heat sealed.

Choose a construction before assigning a finished size

A flat liner may suit a shallow or flexible load. A side-gusset liner can open further across the depth of the carton. Ask the supplier to mark the finished width and length, folds, opening and seal on a drawing. Confirm whether the gusset measurement refers to one fold or its full opened depth.

Example: a 400 × 300 × 250 mm carton

Send these measurements as the carton interior, then indicate how far the liner should extend above the actual fill line. Avoid entering them as finished bag dimensions. In a sample trial, check whether the liner reaches the bottom corners without stretching across them and whether the closure fits beneath the carton flaps.

Trial with the actual load

Check sharp contact points, tension near the seal and excess film at the closure. For a heavy or abrasive load, agree material and a separate performance check. A sample that fits an empty carton only confirms one part of the job.

What should I send for a carton liner quote?

Send the carton interior dimensions, fill height, contents and approximate weight, closure method, film gauge if specified, quantity and destination. Include a photo of the erected carton and filled sample if available.

Hangzhou Hengyi Packaging Material Co., Ltd. reviews custom PE packaging against the intended use and agreed specification. Read Side gusset dimensions and thickness or send your requirements for review.