## Definitions

- Basis Weight

The basis weight of a sheet of paper refers to the designated fixed weight of 500 sheets that is measured in pounds, in the basic sheet size of the paper. Bear in mind that the basic sheet size for all types of paper is not the same. Below is the brief explanation of basis weight for various types of paper.- Type of paper: “Bond”, Ledger, Mimeo, Duplicator, Rag Paper.

Basic size: 17 inches x 22 inches - Type of paper: “Offset”, Book, Text, Coated Paper

Basic size: 25 inches x 38 inches - Type of paper: “Cover”

Basic size: 20 inches x 26 inches - Type of paper: “Tag Stock”

Basic size: 24 inches x 36 inches - Type of paper: “Index”

Basic size: 25.5 inches x 30.5 inches.

- Type of paper: “Bond”, Ledger, Mimeo, Duplicator, Rag Paper.
- Caliper

Meanwhile, calliper refers to the thickness of the sheet of paper. It is expressed in thousandths of an inch. The measurement is done with a micro meter. Usually, paper caliper should not have a + or – that is more than 5 percent variance in a sheet. In general, the relation between paper basis weight and caliper is like this: the greater the paper weight, the greater the caliper or the thicker the paper.Below is the calliper chart for various types of paper:

- Forms Bond Paper (17 inches x 22 inches)

For a sheet of bond paper which basis weight is 10, its average caliper is 0.002. If it has 11.5 of basis weight, the average thickness is 0.0022; 12 basis weight has 0.0025 average thickness; 13.5 basis weight has 0.00275 average thickness; 15 basis weight has 0.003 average thickness; 16 basis weight has 0.00325 average thickness; 18 basis weight has 0.0035 average thickness; 20 basis weight has 0.004 average thickness; 24 basis weight has 0.0045 average thickness; 28 basis weight has 0.0052 average thickness; and 32 basis weight has 0.006 average thickness. - Coated Book Paper (25 inches x 38 inches)

If the coated book paper has glossy surface, then it will have average calliper figures that are different than one with dull surface.For glossy coated book paper, 60 basis weight has 0.0029 average thickness; 70 basis weight has 0.0035 average thickness; 80 basis weight has 0.0038 average thickness; and 100 basis weight has 0.0048 average thickness.

Meanwhile, for dull coated book paper, 60 basis weight has 0.00325 average thickness; 70 basis weight has 0.0037 average calliper; 80 basis weight has 0.00425 average thickness; and 100 basis weight has 0.0054 average thickness.

- Cover Paper (20 inches x 26 inches)

For uncoated cover paper, 50 basis weight has 0.0065 average calliper; 65 basis weight has 0.0097 average thickness; and 80 basis weight has 0.0115 average thickness.As for glossy coated cover paper, 60 basis weight has 0.005 average thickness; 65 basis weight has 0.006 average thickness; 80 basis weight has 0.0075 average thickness; 100 basis weight has 0.0097 average thickness; and 120 basis weight has 0.012 average thickness.

Meanwhile, the dull coated cover paper with 80 basis weight has 0.0085 average thickness and 105 basis weight has 0.011 average thickness.

- Offset Paper, Regular Finish (25 inches x 38 inches)

The offset paper with regular finish with 50 basis weight has 0.004 average caliper; 60 basis weight has 0.0045 average caliper; 70 basis weight has 0.005 average caliper; 80 basis weight has 0.006 average caliper; and 100 basis weight has 0.007 average caliper. - Index Paper (25.5 inches x 30.5 inches)

The index paper with 90 basis weight has 0.007 average caliper; 110 basis weight has 0.009 average thickness; and 140 basis weight has 0.011 average caliper. - Ledger Paper (17 inches x 22 inches)

The ledger paper with 24 basis weight has 0.004 average caliper; 28 basis weight has 0.005 average caliper; 32 basis weight has 0.006 average caliper; and 36 basis weight has 0.006 average caliper. - Tag Paper (24 inches x 36 inches)

Tag paper with 100 basis weight has 0.007 average caliper; 125 basis weight has 0.009 average caliper; 150 basis weight has 0.011 average caliper; 175 basis weight has 0.13 average caliper; and 200 basis weight has 0.15 average caliper.

- Forms Bond Paper (17 inches x 22 inches)

## Equivalent Weight

Even though different types of paper and calliper may have different basic sizes, those papers still can be compared by the use of equivalent weight.

After all, paper weight is the important component you need to take into account when printing. Heavier media frequently conveys quality while providing durability. This is where knowing the weight of the paper to use for printing, in addition to knowing how to convert the various measurements is important. The basis weight is often used in the U.S., but there is also a metric measurement (called grammage), referring to the actual weight of a sheed of media that is cut into 1-by-1 meter square. The measurement used is GSM or grams per square meter.