Comprehensive Calculator Guide
This calculator works out the weight of one sheet, a ream or any number of sheets from the paper’s GSM and size. An 80 gsm A4 sheet weighs about 5 g and a 500-sheet ream about 2.5 kg. It helps with postage and shipping costs, estimating the weight of books and print runs, and comparing papers before printing.
What GSM means
GSM is the weight in grams of one square metre of the paper. Office paper is 80 gsm, premium print paper 100–120, card and covers 200–300 or more.
A-series sizes start from A0 at one square metre, each size half the one before, so A4 is 1/16 m² (0.06237 m² at its rounded 21 × 29.7 cm). For a book, remember each sheet is two pages.
How to Use
- Enter the GSM printed on the ream wrapper, such as 80.
- Choose the size and enter the number of sheets.
- Press “Work out the weight” to see the sheet, total and ream weights.
Formula Used
Sheet weight (g) = GSM × area (m²) | Total = sheet weight × sheets
Practical Examples
- Example 1: an A4 ream
- 500 sheets at 80 gsm: 80 × 0.06237 = 4.99 g a sheet, about 2.49 kg a ream.
- Example 2: heavy A3
- 100 sheets at 120 gsm: about 14.97 g a sheet and 1.5 kg in all; a 500-sheet ream is about 7.48 kg.
Important Tips
- Count sheets, not pages, for a book.
- Add the cover and packaging for shipping.
- Compare GSM, not just price; heavier paper suits double-sided printing.
Common Mistakes to Avoid
- Counting pages instead of sheets.
- Mixing up A4 and US Letter.
- Forgetting GSM is per square metre, not per sheet.
Frequently Asked Questions
- How much does an A4 sheet weigh?
- About 5 g at 80 gsm and 6.2 g at 100 gsm.
- How much does a ream weigh?
- 500 sheets of 80 gsm A4 weigh about 2.5 kg.
- 70 vs 80 gsm?
- 80 gsm is a little thicker and less see-through, better for double-sided printing; 70 is lighter and cheaper.