Compute weight of paper sheets from GSM or US lb Bond and sheet count.
Common paper weights at a glance
| Grammage (GSM) | US lb Bond | Typical use |
|---|---|---|
| 60–70 | 16–18 lb | Lightweight copy, airmail, Bible paper |
| 80 | 20 lb | Standard copy / printer paper |
| 90–100 | 24 lb | Premium letterhead, double-sided print |
| 120 | 32 lb | Heavy letterhead, flyers |
| 160 | 60 lb cover | Brochures, menus, folded cards |
| 250 | 90 lb cover | Light cardstock, postcards |
| 300–350 | 110 lb cover | Heavy cardstock, business cards |
Reference
What is GSM and how is it measured?
GSM stands for grams per square metre (g/m²). It is the mass of a single sheet of paper cut to one square metre. A 100 GSM sheet of paper means every square metre weighs 100 g, regardless of the sheet format. Because the number refers to a fixed area, GSM lets you compare any two papers on equal terms — A4 at 80 GSM has the same paper density as A3 at 80 GSM, only the sheet is larger.
How the US lb Bond system works
US paper weights are reported as the weight in pounds of 500 sheets (a ream) of the paper's basis size. For Bond / Writing / Ledger, the basis size is 17 × 22 inches — a sheet that is cut into four letter-size sheets. So 20 lb Bond means 500 sheets of 17 × 22 in paper weigh 20 pounds. Different paper grades use different basis sizes (Cover, Book, Index), which is why a 60 lb Cover sheet is much heavier than a 60 lb Book sheet. This calculator converts using the Bond basis: 1 lb Bond ≈ 3.7566 GSM.
Converting between GSM and lb Bond
Rule of thumb: GSM ≈ lb Bond × 3.76, or lb Bond ≈ GSM ÷ 3.76.
Quick reference: 16 lb = 60 GSM · 20 lb = 75 GSM · 24 lb = 90 GSM · 28 lb = 105 GSM · 32 lb = 120 GSM.
FAQ
What is the difference between GSM and lb Bond?
GSM is an absolute measure: grams per square metre of paper, independent of sheet size. US lb Bond is relative: pounds per 500 sheets of the paper's basis size (17 × 22 in for Bond). GSM is more universal and makes cross-grade comparison straightforward, while lb Bond is the traditional North American convention for office and writing papers. The calculator accepts either — just switch the tab at the top.
How do I weigh paper to calculate shipping cost?
Multiply GSM by sheet area in m² to get grams per sheet, then multiply by the number of sheets. Example: 100 sheets of US Letter (8.5 × 11 in = 0.0603 m²) at 120 GSM → 100 × 120 × 0.0603 = 723 g, about 1.6 lb. Add envelope or packaging weight on top. Shipping carriers round up, so weighing a small bundle first on a kitchen scale is a reliable cross-check.
What counts as a ream of paper?
In modern usage a ream is 500 sheets. Older definitions used 480 sheets (a "short ream") or 516 (a "printer's ream"), but virtually every office supplier today sells reams of 500. When a product label says "20 lb / 500 sheet ream" it means 500 sheets of 17 × 22 in Bond paper weigh 20 pounds — equivalent to roughly 75 GSM for the sheets you actually use.
Why is my shipped weight heavier than the calculator says?
Three common reasons: packaging adds weight (envelope, box, tape, padding — often 20–100 g), paper absorbs moisture from the air and can gain 3–7% over dry weight in humid conditions, and catalogue GSM is nominal with a tolerance of about ±4%. For shipping, round up to the next pricing tier rather than relying on a precise calculation.
How accurate is the stack-height estimate?
The stack estimate uses a rough rule of 0.1 mm per 80 GSM of uncoated office paper — about 1 mm per 10 sheets of copy paper. Coated, glossy, or premium stocks may be denser (thinner for the same GSM), and loosely stacked sheets trap air and measure taller. For exact thickness, measure a 100-sheet stack with calipers and divide. The calculator's figure is useful for planning shelf space or box size, not for engineering tolerances.
Work out how much a stack of paper weighs from its grammage and sheet count. Pick a standard format (A0–A6, US Letter, Legal, Tabloid) or enter custom dimensions in mm, cm or inches, then set GSM or US lb Bond. The tool returns total weight in grams, kilograms, ounces and pounds, per-sheet weight, sheet area and an estimated stack height. Examples: 500 A4 sheets at 80 GSM weigh 2,494 g — about 2.5 kg per ream of copy paper. 100 US Letter sheets at 120 GSM come to roughly 723 g, useful for estimating shipping cost on a flyer mailing. Switch the tab at the top to work in the North American lb Bond system used on most office paper labels.