ECT and burst grade reference

What the tool does

You select one burst grade from the four single-wall rows the cited 2025 specification supports: 200, 250, 275, or 350 psi. The tool then returns the ECT value commonly paired with that grade in the same row, the row's maximum gross weight in pounds, and the row's maximum combined dimensions in inches, meaning length plus width plus depth. All four values come from one row of the single-wall table in the FBA-hosted 2025 Walmart Corrugated Board Specifications, so the weight and size conditions apply together as a set, not independently.

There is no equation behind this tool. Burst strength and edge compression are separate laboratory measurements, and this tool does not convert one into the other. The pairing shown is a duty-table convention within the cited specification, where each row lists a burst grade, an ECT value and the weight and size conditions that go with it. Treat the output as a reference row, not a prediction of box performance.

• Supported burst grades: 200, 250, 275, and 350 psi only
• Output includes the paired ECT value in lb per inch
• Output includes the row maximum gross weight in pounds
• Output includes the row maximum length plus width plus depth in inches

How to enter the burst grade

The single input is a dropdown of the four burst grades the cited table contains. If your board is rated at a burst grade not in that list, such as 125, 150, or 175 psi single-wall, this tool cannot help, because the cited evidence does not support those pairings. Choose the grade printed on your board certificate or supplier documentation, not the grade you wish the board had.

The default selection is 200 psi. Changing the selection changes the entire row at once, because each grade maps to one fixed set of ECT, weight, and dimension values in the cited table.

Reading the output rows

The report shows four lines: the burst grade you entered, the common single-wall duty-table pairing in ECT, the reference row maximum gross weight, and the reference row maximum length plus width plus depth. The gross weight is the total shipping weight of the packed box, product plus dunnage plus the box itself. The combined-dimension figure is the sum of the three outside box dimensions, not any single dimension.

Both conditions must be satisfied simultaneously. A box that meets the weight limit but exceeds the combined-dimension limit does not fit the row, and vice versa. When you evaluate a candidate box, check both numbers against your actual packed weight and your actual measured outside dimensions before treating the row as applicable.

Worked examples

Starting scenario: select 200 psi. The tool returns a 32 ECT pairing, a 65 lb maximum gross weight, and a 75 in maximum combined dimension. If your packed box weighs 60 lb and measures 24 by 18 by 16 in, the combined dimension is 58 in, so both conditions are met for this row.

Changed scenario: select 250 psi. The pairing rises to 40 ECT, the gross-weight limit rises to 80 lb, and the combined-dimension limit rises to 85 in. The reason the output changes is that each grade points to a different row of the cited table, and higher burst grades in this table carry progressively higher weight and size allowances. The same 60 lb, 58 in box still fits, but a 78 lb shipment that would have exceeded the 200 psi row's 65 lb limit now fits the 250 psi row, provided the board actually meets that grade.

Why UPS guidance differs

Parcel carrier guidance, including UPS published box strength guidelines, uses different combinations of burst or ECT values with different weight and size conditions than this table. The cited Walmart specification is a named channel document, not universal carrier guidance. A box that satisfies the Walmart row may not satisfy a UPS recommendation for the same shipment, and the reverse also holds. When shipping by parcel, check the carrier's own current guidance separately rather than assuming the two align.

Limitations you should keep in mind

This is a named historical specification reference. It is not a statement of current Walmart acceptance, and a matched row does not guarantee equivalent protection in transit. Material choice, board construction and finished-box testing still determine real performance. Use this lookup as a screening reference and confirm the actual current specification for your channel before committing to a board grade.

Questions about ect and burst grade reference