Understanding Basis Weight in Packaging Paper

Basis Weight in Packaging Paper – Complete Guide for Buyers

Choosing the right packaging paper starts with understanding basis weight — the standard measure of paper heaviness in the United States. If you’ve seen terms like 30# kraft, 50 lb newsprint, or 80# bogus paper, you’ve already encountered basis weight. The key is knowing what those numbers actually mean so you can select the right material for your needs.

At Strong Converting, we use the 24″ × 36″ standard sheet size for packaging paper basis weights. This guide will explain what that means, how it compares to GSM (grams per square meter), and how thickness (caliper) factors in. We’ll also cover how linerboard and chipboard are measured differently, so you can make informed buying decisions across multiple product types.

What Is Basis Weight?

Basis weight is the weight (in pounds) of 500 sheets of paper cut to a specific “basis size” for that paper grade. For packaging kraft, bogus, and newsprint, that basis size is typically 24″ × 36″.

Example:
If a kraft paper is labeled 50#, it means 500 sheets measuring 24″ × 36″ weigh 50 pounds.

Why the 24×36 Standard Matters

Because the U.S. system ties the weight number to a specific sheet size, the basis size changes by paper type. A 50# packaging kraft is not the same thickness as a 50# printing paper — they use different base dimensions.

For packaging papers like kraft, bogus, and newsprint, the 24×36 standard means you can directly compare their basis weights to each other.

Example:

  • 50# kraft roll ≈ 50# bogus roll in general thickness and strength.

  • But 50# kraft roll is much thinner than a 50# cover stock from the printing world.

Basis Weight vs. GSM (Metric System)

Outside the U.S., paper weight is measured in grams per square meter (GSM) — a straightforward density measure that applies equally to all grades.

For packaging paper with a 24×36 basis, you can convert by multiplying basis weight by 1.63. For example:

  • 30# kraft ≈ 49 gsm

  • 50# kraft ≈ 81 gsm

  • 80# kraft ≈ 130 gsm

GSM is a universal system — it allows you to compare different paper grades side-by-side without worrying about base sheet size differences.

Basis Weight vs. Caliper (Thickness)

Caliper measures paper thickness in thousandths of an inch (mils or points). For packaging kraft:

Within the same paper type, higher basis weight means thicker, stronger paper. But coatings, fiber type, and density can change this — so for exact fit in machinery or to meet postal specs, check both basis weight and caliper.

Linerboard Basis Weight (1,000 sq ft Scale)

Linerboard — the outer layer of corrugated boxes — uses a 1,000 square foot basis. Common grades stocked at Strong include 26#, 33#, 42#, 56# and 69#.

  • 42# linerboard is the industry standard for most corrugated boxes.

  • Higher numbers mean greater stacking strength and puncture resistance.

Bag Kraft Basis Weight (3,000 sq ft Scale)

Some kraft papers, especially bag stock, are weighed on a 3,000 square foot basis.

  • A 50# bag kraft is thicker than a 50# 24×36 kraft because the base sheet is larger in the measurement system.

Chipboard Measured by Caliper (Points)

Chipboard — used for pads, carton stiffeners, and dividers — is not sold by basis weight.
Instead, it’s measured in points (pt):

  • 1 pt = 0.001″ thick.

  • Common: 18 pt (light), 30 pt (medium), 50 pt+ (heavy duty).
    Points make it easy to match thickness to protection needs.

Choosing the Right Weight for Your Job

Light Duty (30–40#)

  • Wrapping small or delicate items

  • Flexible void fill

  • Surface protection for scratch prevention

Medium Duty (50–60#)

  • Bundling items

  • Wrapping heavier tools or components

  • General shipping protection

Heavy Duty (70–80#)

  • Sharp-edged parts

  • Construction floor covering

  • Industrial wrapping that resists tearing

Why This Matters for Buyers

Knowing your paper’s basis weight, measurement scale, and thickness ensures you don’t overpay for strength you don’t need — or under-protect your products.

At Strong Converting, all our kraft, bogus, and newsprint rolls are listed with basis weight and caliper, so you can match exactly to your needs.