PACKAGING CALCULATOR
Estimate unfolded PP corrugated sheet area and theoretical sheet weight before die cutting. Use the unfolded blank dimensions from the approved box drawing, not the finished internal or external box dimensions.
INPUTS
QUICK START
CALCULATION METHOD
Sheet area (m²) = unfolded length (mm) × unfolded width (mm) ÷ 1,000,000
Theoretical sheet weight (g) = sheet area (m²) × GSM
For the default example, a 900 × 652 mm unfolded sheet has an area of 0.5868 m². At 800 GSM, the theoretical sheet weight is 469.44 g before die cutting.
GSM SPECIFICATION GUIDE
GSM is the mass of sheet material per square metre. A 750 GSM corrugated polypropylene sheet has a theoretical material mass of 750 grams for each square metre before die cutting. Buyers use GSM with the unfolded blank area to estimate material weight, compare preliminary specifications and prepare shipping or quotation information.
GSM is a material-weight specification, not a complete performance rating. Load capacity and stacking behavior also depend on the PP formulation, thickness, flute structure, box geometry, folds, openings, load distribution and handling conditions.
GSM and thickness are not the same measurement. GSM measures grams per square metre, while thickness measures the distance between the two outer surfaces of the sheet, normally in millimetres.
Two sheets with the same nominal thickness can have different GSM values because the skin weight, flute geometry and material formulation may differ. Likewise, a higher GSM does not automatically mean a thicker sheet. Confirm both values for the final packaging specification.
Convert the sheet length and width from millimetres to square metres, then multiply the area by GSM:
Area (m²) = length (mm) × width (mm) ÷ 1,000,000
Theoretical weight (g) = area (m²) × GSM
For dimensions already stated in metres, multiply length × width to obtain square metres, then multiply by GSM.
Use the total unfolded blank area from the approved die-line—not the finished internal box length × width. A folded box includes side walls, end walls, flaps, locks and joining areas, so its flat blank is larger than the finished footprint.
Theoretical box blank weight (g) = total unfolded blank area (m²) × GSM. If the box uses more than one sheet or separate components, calculate each blank and add the results.
The calculation gives the theoretical weight of the full blank before die cutting. Finished box weight can be lower after ventilation holes, drainage holes, hand holes and waste areas are removed. It can also change when locks, welds, reinforcements, handles, printing, dividers or other components are added.
Material and manufacturing tolerances can also create a small difference. Use the calculator for preliminary engineering and purchasing estimates; use an approved production sample for final box weight.
| Unfolded blank | GSM | Area calculation | Theoretical weight |
|---|---|---|---|
| 900 × 652 mm | 800 GSM | 900 × 652 ÷ 1,000,000 = 0.5868 m² | 0.5868 × 800 = 469.44 g (0.469 kg) |
| 1,200 × 800 mm | 750 GSM | 1,200 × 800 ÷ 1,000,000 = 0.96 m² | 0.96 × 750 = 720 g (0.720 kg) |
| 650 × 480 mm | 600 GSM | 650 × 480 ÷ 1,000,000 = 0.312 m² | 0.312 × 600 = 187.2 g (0.187 kg) |
These examples calculate full, rectangular, pre-die-cut blanks. They do not estimate material removed or components added during manufacturing.
GSM means grams per square metre. It states how many grams one square metre of the specified corrugated plastic sheet theoretically weighs.
No. GSM measures material mass per unit area; thickness measures sheet depth in millimetres. Both values should be confirmed for a packaging specification.
Calculate the sheet area in square metres, then multiply that area by the GSM. For millimetres: length × width ÷ 1,000,000 × GSM.
Use the total unfolded die-line or blank area, multiply it by GSM, and add the theoretical weight of any separate sheet components. Do not use only the finished box footprint.
Die cutting removes material, while printing, welding, handles, locks, reinforcement and inserts can add or change weight. Material and production tolerances also affect the finished result.
VERIFY THE REAL SPECIFICATION
Share the dimensions, GSM, thickness, quantity and box structure. We can review the actual design and manufacturing specification before sampling or quotation.
