US paper is labelled by the weight of 500 sheets of its “basic size”, which differs by grade – so 20 lb bond and 50 lb text are about the same paper (75 gsm). Grams per square metre avoid that confusion. Knowing the sheet weight also helps estimate postage for mailings.
How to use the Paper Weight Calculator
- I know the
- Grammage
- Basis weight
- Paper grade (basic size)
- Paper size
- Number of sheets
Results update as you type, and every field accepts the units shown in its menu.
How it works
Choose whether you know gsm or basis weight (with the paper grade), the sheet size and the number of sheets.
Tips
- Track a typical week before planning – real figures beat estimates.
- Break big tasks into smaller pieces and plan buffer time for interruptions.
- Re-run the numbers when your inputs change so plans stay realistic.
- Use results as a guide for decisions, not as a precise prediction.
Common mistakes to avoid
- Counting calendar days when the deadline is in working days (or the reverse).
- Forgetting breaks, setup and handover time.
- Assuming every day is as productive as your best day.
Inputs explained
| Field | What to enter |
|---|---|
| I know the | Choose one: Grammage (gsm), US basis weight (lb) |
| Grammage | In gsm |
| Basis weight | In lb |
| Paper grade (basic size) | Choose one: Bond / writing (17 × 22 in), Text / book (25 × 38 in), Cover (20 × 26 in), Index (25.5 × 30.5 in) … |
| Paper size | Choose one: US Letter (8.5 × 11 in), US Legal (8.5 × 14 in), Tabloid / Ledger (11 × 17 in), Half letter (5.5 × 8.5 in) … |
| Number of sheets | A number |
What each result means
- Equivalent bond weight = [Grammage]×500×374×0.00064516÷453.59237
- Weight of one sheet = [Grammage]×[Paper size]
- Total weight = [Weight of one sheet]×[Number of sheets]
Example values
How the main result changes when Grammage changes and everything else stays at the example values above:
| Grammage (gsm) | Total weight (kg) |
|---|---|
| 40 | 1.25 |
| 60 | 1.87 |
| 80 | 2.49 |
| 100 | 3.12 |
| 120 | 3.74 |
| 160 | 4.99 |
Formula
Basis weight to gsm = lb × 453.592 ÷ (500 × basic sheet area in m²)Weight of one sheet = gsm × sheet areaTotal weight = sheet weight × quantityWorked example
Inputs — I know the: Grammage (gsm); Grammage: 80 gsm; Basis weight: 20 lb; Paper grade (basic size): Bond / writing (17 × 22 in); Paper size: A4 (210 × 297 mm); Number of sheets: 500.
Results — Grammage = 80 gsm; Equivalent bond weight = 21.3 lb; Weight of one sheet = 4.99 g; Total weight = 2.49 kg.
Key terms
- Basis weight
- Weight in pounds of 500 sheets of a paper's basic size.
- GSM
- Grams per square metre.
Frequently asked questions
What is 20 lb paper in gsm?
About 75 gsm (bond).
How much does a ream of A4 80 gsm weigh?
About 2.5 kg (5.5 lb).
Why is 50 lb text the same as 20 lb bond?
Basis weight uses different basic sheet sizes for each grade; both are about 75 gsm.
What formula does the Paper Weight Calculator use?
Basis weight to gsm = lb × 453.592 ÷ (500 × basic sheet area in m²).