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Open toolPaper Weight Calculator
Calculate the total weight of any stack, ream, or print run of paper from sheet width (mm), sheet height (mm), paper grammage (GSM in g/m²), and sheet count.
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Enter the inputs, then select Calculate.
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How Paper Weight Is Calculated from GSM (Grams per Square Meter)
Paper grammage (GSM) measures the mass in grams of a single square meter (1,000 mm x 1,000 mm = 1,000,000 mm²) of paper. Multiplying a sheet's area in square meters by its GSM gives the exact mass of one sheet.
Single Sheet Area (m²) = (Width in mm x Height in mm) / 1,000,000. Total Mass (grams) = Sheet Area (m²) x Grammage (g/m²) x Sheet Count. Total Mass (kg) = Total Mass (grams) / 1,000.
Standard ISO A0 paper has an area of exactly 1.0 m², and each step down the A-series halves the area (A4 = 1/16 m² = 0.06237 m² for 210 x 297 mm).
Standard Paper Sizes, GSM Weights, and 500-Sheet Ream Mass Chart
Quick reference for ISO A-series and North American sheet dimensions, single-sheet mass, and 500-sheet ream weights across common GSM grades.
| Paper Size | Dimensions (mm) | Sheet Area (m²) | 80 GSM (1 Sheet / 500 Ream) | 120 GSM (1 Sheet / 500 Ream) | 300 GSM Cardstock (100 Sheets) |
|---|---|---|---|---|---|
| ISO A4 | 210 x 297 mm | 0.06237 m² | 4.99 g / 2,495 g (2.50 kg) | 7.48 g / 3,742 g (3.74 kg) | 1,871 g (1.87 kg) |
| ISO A3 | 297 x 420 mm | 0.12474 m² | 9.98 g / 4,990 g (4.99 kg) | 14.97 g / 7,484 g (7.48 kg) | 3,742 g (3.74 kg) |
| ISO A5 | 148 x 210 mm | 0.03108 m² | 2.49 g / 1,243 g (1.24 kg) | 3.73 g / 1,865 g (1.86 kg) | 932 g (0.93 kg) |
| US Letter (8.5 x 11 in) | 215.9 x 279.4 mm | 0.06032 m² | 4.83 g / 2,413 g (2.41 kg) | 7.24 g / 3,619 g (3.62 kg) | 1,810 g (1.81 kg) |
| US Legal (8.5 x 14 in) | 215.9 x 355.6 mm | 0.07677 m² | 6.14 g / 3,071 g (3.07 kg) | 9.21 g / 4,606 g (4.61 kg) | 2,303 g (2.30 kg) |
| SRA3 (Untrimmed Print) | 320 x 450 mm | 0.14400 m² | 11.52 g / 5,760 g (5.76 kg) | 17.28 g / 8,640 g (8.64 kg) | 4,320 g (4.32 kg) |
How to Calculate Paper Weight Step by Step
Enter sheet dimensions in millimeters, paper grammage in g/m², and the total number of sheets.
Enter Sheet width (mm) and Sheet height (mm)
Type the sheet width and height in millimeters (for example, 210 and 297 for A4, or 215.9 and 279.4 for US Letter). If your size is in inches, multiply inches by 25.4 to get millimeters.
Input and settings
Enter Paper grammage (g/m² / GSM)
Enter the paper's GSM rating (such as 80 for standard office copy paper, 130-170 for flyers/brochures, or 250-350 for business cards and covers).
Tool result
Set Sheet count and calculate total mass
Enter the total number of sheets (for example, 100, 500 for one ream, or 2500 for a 5-ream carton) and select Calculate result.
Review the details
Practical Mailing, Printing, and Freight Examples
Estimate postage brackets, brochure print shipping weight, and ream weights.
100 sheets of A4 80 GSM office paper (default baseline)
An A4 sheet measures 210 mm x 297 mm = 0.06237 m². At 80 g/m², one sheet weighs 4.9896 g, and 100 sheets weigh 498.96 g (0.499 kg).
Calculating postal weight for a multi-page booklet or mailpiece
Before sealing a catalog or legal packet in an envelope, calculate the exact gram weight of the inner sheets plus the heavier cover stock to stay under postal weight tiers.
Estimating commercial print pallet weight (5,000 A3 flyers at 150 GSM)
At 297 x 420 mm and 150 GSM, 5,000 sheets weigh 0.12474 x 150 x 5,000 = 93,555 g (93.56 kg) before carton packaging.
How to Read the Gram and Kilogram Output
Compare nominal paper weight against real-world humidity, ink, and packaging tolerances.
The result is the estimated total paper mass. Estimate a stack's nominal paper mass from sheet size and grams per square meter.
This uses nominal paper area and grammage; coatings, packaging and moisture changes are not inferred.
Numerical output shows up to 12 significant digits. Floating-point arithmetic and display rounding can affect the last digits.
- Example input
- Sheet width (mm) = 210; Sheet height (mm) = 297; Paper grammage (g/m²) = 80; Sheet count = 100
- Example output
- 498.96 g
Converting US Basis Weight (lb) and Inches to Millimeters
Check your measurement units before running the calculation.
Always enter dimensions in millimeters (1 inch = 25.4 mm; 1 cm = 10 mm). Entering 8.5 x 11 instead of 215.9 x 279.4 will underestimate the area by a factor of 645.16.
If your paper specifies US Basis Weight in pounds (lb), convert to GSM first: 20 lb bond = 75 GSM, 24 lb bond = 90 GSM, 28 lb bond = 105 GSM, 80 lb text = 118 GSM, and 80 lb cover = 216 GSM.
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Open toolPaper Weight Calculator: Frequently Asked Questions
Answers about using Paper Weight Calculator and understanding its results.
How much does 1 sheet and 1 ream (500 sheets) of A4 80 GSM paper weigh?
One sheet of A4 (210 x 297 mm) 80 GSM paper weighs 4.99 grams (0.176 oz). A standard 500-sheet ream weighs 2,494.8 grams (about 2.5 kg or 5.5 lbs) excluding the wrapper.
What is the formula to calculate paper weight from GSM?
Multiply Width (mm) by Height (mm), divide by 1,000,000 to get the sheet area in square meters (m²), then multiply by the GSM (g/m²) and the number of sheets: Grams = (Width_mm x Height_mm / 1,000,000) x GSM x Sheets.
How do I convert inches to millimeters for US Letter or Tabloid sizes?
Multiply inches by 25.4. US Letter (8.5 x 11 in) is 215.9 x 279.4 mm, US Legal (8.5 x 14 in) is 215.9 x 355.6 mm, and Tabloid/Ledger (11 x 17 in) is 279.4 x 431.8 mm.
What is the difference between GSM and lb (pound) paper weight?
GSM (grams per square meter) measures the mass of a fixed 1 m² sheet regardless of paper grade. US pound (lb) basis weight measures 500 sheets of that grade's uncut parent sheet size, which differs between bond, text, and cover stocks.
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