Paper Weight (GSM) Calculator

Work out paper weight (gsm) instantly with clear inputs, formula shown and shareable results.

About Paper Weight (GSM) Calculator

Grammage is grams per square metre, so a sheet's weight is its area in square metres multiplied by the gsm figure. Postage brackets are decided by total weight, which is why a 120 gsm A4 letter at five grams a sheet can push a mailing into the next price band.

Formulas

Sheet weight

grams = width m x height m x gsm

Total weight

kg = sheet weight x sheets / 1000

Worked example

With the default values below, Paper Weight (GSM) Calculator returns Weight of one sheet of 7.484. Change any input above and every figure here is recalculated in your browser.

Inputs used

Paper weightminimum 1 gsm: 120 gsm
Sheet widthminimum 1 mm: 210 mm
Sheet heightminimum 1 mm: 297 mm
Number of sheetsminimum 1: 500

Results

Weight of one sheet: 7.484 g
Weight of the whole quantity: 3.7422 kg
Sheets per kilogram: 133.6
Area of one sheet: 0.06237 m2

Step by step

1Values used
2Sheet weight
3Total weight
4Weight of one sheet= 7.484 g
5Weight of the whole quantity= 3.7422 kg
6Sheets per kilogram= 133.6
7Area of one sheet= 0.06237 m2

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 5 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is the Paper Weight (GSM) figure worked out?

grams = width m x height m x gsm. Grammage is grams per square metre, so a sheet's weight is its area in square metres multiplied by the gsm figure.

Why does this matter?

Postage brackets are decided by total weight, which is why a 120 gsm A4 letter at five grams a sheet can push a mailing into the next price band.

What do I need to enter?

Enter paper weight, sheet width, sheet height, number of sheets. The defaults shown are a realistic worked example — swap in your own figures to get a result you can use.