Free Paper Weight Calculator

Whether you need a paper grammage calculator for metric measurements or a basis weight to grammage converter for imperial values, this tool applies the standard paper weight formula to compute the paper weight per sheet instantly. It handles both grammage (gsm) and basis weight (lb), making it easy to switch between systems and to find the total weight for any number of sheets.

Grammage (gsm) – The Metric Standard

Grammage, expressed in grams per square meter (g/m² or gsm), is the most direct measure of paper weight. It tells you how much a square‑meter sheet of a given paper weighs. Heavier grammages generally mean a stiffer, more substantial paper, but grammage is not a direct indicator of thickness. Common values include:

• Office copy paper: 75–120 gsm
• Photo paper: 180–240 gsm
• Cardstock and cover stock: 250–350 gsm

The selection of grammage also influences print quality and feel, though personal preference often plays a role.

Basis Weight – The Imperial Alternative

In North America, paper weight is often quoted as basis weight – the weight in pounds of a ream (500 sheets) at a specific basic sheet size. The basic size depends on the stock type:

• Bond: 17″ × 22″
• Text (Book): 25″ × 38″
• Tag: 24″ × 36″
• Index: 25.5″ × 30.5″
• Bristol: 22.5″ × 28.5″
• Cover: 20″ × 26″

Because the basic size varies, the same basis weight number (e.g., 20 lb) corresponds to different actual grammages for different stocks. For example, 20 lb bond is approximately 75 gsm, while 20 lb cover is closer to 54 gsm. The calculator automatically handles these conversions using the relevant basic sheet area.

Quick Conversion Reference

The table below gives approximate grammage equivalents for common basis weights across selected stock types.

Stock	Basic Size (in)	20 lb	24 lb	28 lb	32 lb	80 lb	100 lb
Bond	17×22	75 gsm	90 gsm	105 gsm	120 gsm	—	—
Text	25×38	—	—	—	—	118 gsm	148 gsm
Cover	20×26	—	—	—	—	163 gsm	203 gsm

Note: The equivalents are approximate and can vary slightly between manufacturers.

How to Calculate Paper Weight

The calculator uses two formulas depending on the metric chosen.

Using Grammage

When grammage is known, the weight of a single sheet is:

$$\text{Weight} = \text{length} \times \text{width} \times \text{grammage}$$

where length and width are in meters and grammage in g/m², yielding weight in grams.

Using Basis Weight

When basis weight is known, the formula becomes:

$$\text{Weight per sheet} = \frac{\text{basis weight} \times (\text{sheet length} \times \text{sheet width})}{\text{basic sheet area} \times 500}$$

Here, basis weight is in pounds, dimensions in inches (consistent with the basic sheet area), and the denominator accounts for ream size.

Total Weight for Multiple Sheets

Simply multiply the per‑sheet weight by the number of sheets:

$$\text{Total weight} = \text{weight per sheet} \times n$$

Step-by-Step Use of the Calculator

1. Select the unit system: either Grammage (gsm) or Basis Weight (lb).
2. Enter the value: if using grammage, input the gsm; if using basis weight, choose the stock type and enter the basis weight.
3. Provide sheet dimensions: enter the length and width of the paper sheet.
4. View the weight per sheet: the result updates in real time.
5. Adjust the quantity to get the total weight for your desired number of sheets.
6. Convert between systems: the tool will automatically show the equivalent grammage or basis weight when you toggle units.

Example: A4 Copy Paper (70 gsm)

Imagine you need the weight of five reams (2,500 sheets) of 70 gsm A4 paper. A4 dimensions are 0.210 m × 0.297 m, giving an area of 0.06237 m².

Per‑sheet weight:

$$0.06237 \times 70 = 4.366\ \text{g}$$

Total for 2,500 sheets:

$$4.366 \times 2,500 = 10,915\ \text{g} = 10.915\ \text{kg}$$

So, five reams weigh about 10.9 kg.

Additional Considerations

The same calculation principle – area times areal density – applies to many other flat materials, such as metal sheets, plastic films, or textile panels. While this guide focuses on paper, the underlying approach is universal.

By understanding both grammage and basis weight, and using a dedicated paper weight calculator, you can avoid guesswork in shipping, printing, and inventory management. The tool ensures accurate paper weight per sheet results and seamless basis weight to grammage conversion.