Understanding Basis Weight
Basis weight is a fundamental measurement in the paper industry that indicates the weight of paper relative to a standard area. It helps determine the thickness, strength, and cost of paper products.
Formula
The basis weight formula is straightforward:
$$\text{Basis Weight} = \text{Basic Paper Area} \times \text{Weight Per Unit Area}$$
For metric conversion (where Basis Weight is in g/m² and the imperial weight is in lb):
$$\text{Basis Weight} = \text{Imperial Weight} \times 703.07$$
Example Calculation
Let's calculate the basis weight for a standard paper:
- Basic Paper Area: 50 in²
- Weight Per Unit Area: 0.015 lb/in²
Calculation:
$$\text{Basis Weight} = 50 \text{ in}^2 \times 0.015 \text{ lb/in}^2 = 0.75 \text{ lb}$$
Metric Conversion:
$$\text{Basis Weight} = 0.75 \text{ lb} \times 703.07 = 527.30 \text{ g/m}^2$$
This basis weight would be typical for medium-weight printing paper.
Common Paper Basis Weights
- Bond Paper: 16-24 lb (60-90 g/m²)
- Text Paper: 60-100 lb (90-150 g/m²)
- Cover Stock: 65-110 lb (175-300 g/m²)
- Cardboard: 200+ lb (540+ g/m²)
Understanding basis weight helps you select the right paper for your printing, packaging, or writing needs.