How to Measure Plastic Sofa Covers: Gussets and Sample Fit
To measure plastic sofa covers for a custom bag order, first record the sofa's maximum outside width, depth and height in its actual packing condition. Give those measurements and photographs to the bag supplier. Then agree a drawing that identifies the opening, seals, side gussets and finished-bag dimensions, and check a sample on the intended sofa before approving production.
The furniture measurements describe what goes inside the bag. They are not automatically the dimensions to put on a bag purchase order. This guide is for formed PE sofa cover bags with side gussets, used by furniture manufacturers, packing teams and packaging distributors.
Measure the sofa as it will actually be packed
A two-seat or three-seat label is a product category, not a complete size specification. Arm shape, back height, feet, cushions and protective packing can change the space a cover needs. More Polythene's furniture-bag guidance starts with the widest point, height and front-to-back depth and calls for clearance around corners and feet.
Record the packing state before measuring: whether legs are fitted or removed, cushions are in place or packed separately, and corner protectors or other layers will sit inside the cover. Measure that configuration consistently. Do not compress upholstery just to obtain a smaller number unless that compression is part of the specified packing process.
- Outside width: the greatest side-to-side span of the packed sofa, including the outermost arms or protection.
- Outside depth: the greatest front-to-back span, including a projecting back, feet or packing.
- Outside height: the greatest height in the stated packing orientation, using a clearly identified bottom reference.
Take straight reference measurements across the outside envelope rather than following the upholstery's curves with the tape. Supply front, side and rear photographs with the measurement directions marked. For a sectional, identify whether modules are covered separately or as an assembled unit; include a sketch for an L-shaped arrangement.
A sofa body measures 2,160 mm across before packing. A protector adds 20 mm at each end. The packed outside width is therefore 2,160 + 20 + 20 = 2,200 mm. Send 2,200 mm as the measured packed width, together with the separately measured packed depth and height. This calculation does not determine the bag width or a loading allowance.
Ask what each bag dimension actually measures
A size string such as width × gusset × length is incomplete without its definitions. Interplas's side-gusset measuring sheet uses outside dimensions. Richmond Plastics' measurement guide specifies interior dimensions and measures side-gusset depth when extended. These are supplier conventions, not interchangeable descriptions of usable space.
Request a drawing of the proposed bag with the opening and seals shown. Use the supplier's symbols only after the drawing explains their endpoints, including the material needed beyond the sofa for the intended coverage or closure.
| Drawing item | What to identify | Why it matters |
|---|---|---|
| Opening and sealed edges | Which edge opens, where seals run, and how the bag is presented for application. | The opening must suit the planned route onto the furniture. |
| Width and side gusset | Face width, fully opened side depth and any folded-width dimension, each with its own label. | Three numbers may describe different features in different catalogs. |
| Length and usable coverage | Measurement endpoints; whether a quoted length includes a seal, tail, lip or closure portion. | Overall finished length and usable covering length are different questions. |
| Measurement basis | Inside or outside dimensions, units and agreed measurement condition. | A catalog dimension cannot be assumed to be an internal clearance. |
| Acceptance limits | Nominal dimensions, agreed tolerances and how the supplied sample or production bags will be checked. | The order needs a common basis for accepting the dimensions. |
Keep film thickness separate from the bag's width, gusset and length. It should describe one film wall, with the unit and tolerance agreed. A thicker bag is not a substitute for correcting an unsuitable opening or an undersized shape. The PE film thickness and tolerance guide explains the measurement distinction.
Separate fold-in depth from the fully opened gusset
A side gusset is the folded-in section along the side of a bag that opens to provide depth. The word gusset alone does not tell you which measurement the supplier has quoted.
Some drawings label the inward fold; others label the fully opened side depth. Associated Bag's side-gusset explanation distinguishes the fold value from a depth twice that value. Other conventions differ again: Polybags' size guide presents a closed width, opened width and length. Do not read that three-number format as face width × side depth × length without checking.
For an ordinary symmetrical side pleat, assume each half of the opened side panel is 200 mm. Its fully opened depth is 200 + 200 = 400 mm. A drawing labeling the fold-in value as 200 mm and another labeling the full depth as 400 mm could be describing this same pleat.
That does not prove the two bags are identical. Their face width, length, opening, seal layout and measurement basis must also match. Do not halve or double a quoted number when the actual drawing does not establish this fold arrangement.
Check the route onto the sofa, not only the final position
A bag may appear large enough around the sofa once positioned but still be awkward to apply over projecting arms or a tall back. Tell the supplier whether the planned procedure lowers the cover over an upright sofa or loads the furniture through an opening in another orientation. Ask for a design that can follow that procedure.
Identify the cross-section that the opening must pass during application. Note where a foot, arm, corner protector or cushion can catch the film. Then show where the cover should finish and what material must remain for the chosen closure or overlap. These requirements help the supplier propose the bag dimensions and clearance; there is no single extra-inch allowance that resolves every furniture shape and opening layout.
Use the normal furniture-handling method during the trial. The cover should not need force-stretching to make an undersized bag fit, and the film should not be used as a lifting point. If the packing route changes, review the drawing and sample again.
Turn a sample fit into a clear revision decision
Trial the proposed bag on the actual sofa configuration, using the intended application route. Open the gussets fully, apply the cover, arrange the intended overlap or closure, and observe the normal packing steps. Record the sample identity and drawing revision before discussing a change.
Start with the models most likely to challenge the design: the widest arms, greatest depth, tallest back and most prominent protected corners. The sofa with the largest overall width is not automatically the only model that needs checking. A smaller model may have a different shape or application route.
| Observation | Record for the supplier | Review before approval |
|---|---|---|
| The mouth catches on both arms before the bag reaches its final position. | Photograph the application stage, arm span, packing orientation and opening edge. | Review opening geometry and the route. Extra overall length alone may not solve the restriction. |
| The cover reaches the base, but pulls tight across a protected rear corner. | Show the exact corner, protector and fully opened gusset; note any visible damage. | Check local clearance, gusset deployment and bag dimensions before attributing the problem to thickness. |
| The cover applies freely, but does not leave the requested material for closure. | Mark the required coverage line and closure arrangement on a photograph. | Review usable length and the closure portion against the drawing. |
| Loose material trails into a handling area. | Photograph the excess and identify the packing step where it gets in the way. | Review bag size, permitted folding and closure procedure while preserving application clearance. |
Agree what a satisfactory fit means for the order: application without forced stretching, the intended coverage and closure, and no observed tearing or seal opening during the defined fit check. If a revision changes the opening, gusset or length, repeat the affected checks. Fit approval is separate from validating the complete pack for transport or storage protection.
Approve the drawing, sample and order on the same basis
A useful enquiry separates the measured furniture from the proposed bag. The following example shows the information to send without inventing a finished bag size.
- Furniture: Model A sofa, assembled, legs fitted, cushions in their stated packing position; corner protectors included.
- Measured packed envelope: maximum outside width 2,200 mm × depth 950 mm × height 900 mm, with three marked photographs.
- Requested procedure: lower a formed cover over the upright sofa; supplier to confirm a suitable opening and bag layout. A marked photograph shows the required final coverage.
- Drawing request: identify opening, seals, full gusset depth, measurement endpoints, inside/outside basis and nominal dimensions with agreed tolerances.
- Approval request: provide a sample linked to the proposed drawing revision for a fit check on Model A and the other listed furniture configurations.
Add the quantity required for each proposed size, destination country, expected order frequency and packing-station supply format. Ask the quotation to state minimum order allocation, sample charges and freight, production lead time and its starting conditions. Confirm these for the sofa-cover order rather than carrying over terms from another product.
Before production, retain the approved drawing, sample reference, material and single-wall thickness specification, dimensional acceptance limits, packing details and the list of furniture configurations checked. For a repeat order, confirm that the sofa, protection, bag revision and application procedure are unchanged.
Prepare a custom sofa-cover bag enquiry
TIANFENG supplies formed plastic sofa cover bags with side gussets. Send the packed furniture measurements, marked photographs, intended application route, quantity and destination so the proposed bag drawing and sample requirements can be discussed.
Review custom plastic sofa covers →For a bag lining the inside of a carton or pallet box, use the separate box-liner measurement guide. Its inside-container geometry should not be used as the sizing rule for a sofa's external cover.
Plastic sofa cover sizing FAQ
Can I order by the sofa's seating capacity alone?
Use it as a description, then provide the actual packed outside measurements and configuration. Two sofas described as three-seat models can have different arms, backs, feet and packing. A supplier's catalog fit label applies to its particular product and stated dimensions.
Does a larger gusset automatically make the cover fit?
No. It changes one aspect of the bag's shape. Face width, opening orientation, usable length, seals and the application route also matter. Confirm what the gusset number measures, then trial the proposed complete bag.
Can one sample approve a whole range of sofas?
Only the configurations actually checked are evidenced by that trial. Select representative shapes and packing states with the supplier and record which models were tested. Changes to furniture, protective layers or the application route may require a new fit check.
Measurement references
These supplier references explain measurement conventions and furniture-bag considerations. Their stock sizes, allowances and commercial terms are not TIANFENG specifications.
- More Polythene: furniture dimensions and custom bag enquiries.
- Interplas: side-gusset bag dimensions and outside measurement basis.
- Richmond Plastics: interior measurements and extended gusset depth.
- Polybags: closed and opened bag-size notation.
- Associated Bag: the distinction between gusset fold and expanded depth.