Paper Weight Explained: lb vs gsm — Why 80 lb, 80 gsm and Tomoe River 52 g/m² Differ
Paper Weight Explained: lb vs gsm — Why 80 lb, 80 gsm and Tomoe River 52 g/m² Differ
Pounds per ream, gsm and g/m² explained for notebook buyers: why 80 lb is about 84 gsm on Taiwan's 31×43 in basis but 118 gsm as US text, why Tomoe River is 52 g/m² not 52 lb, and how to brief a custom notebook supplier.
Paper Weight Explained:
lb vs gsm
Why “80 lb”, 80 gsm and Tomoe River 52 g/m² are not the same thing
“Just use 80 lb paper for the inside pages.”
It sounds precise, but a paper mill, a printer in Taiwan and a buyer in the US can read that number three different ways. Before you compare papers, confirm the unit behind the number.
Two 80s, not necessarily one spec
Basis: 31 × 43 in · 500 sheets per ream
On that basis, 80 lb works out to about 84.4 g/m². Change the basis sheet size or sheet count and the result changes too.
g, gsm, g/m² and lb — what is the difference?
Some people say “pounds” loosely to mean paper weight; some specifications really do mean the weight of one ream. A paper wrapper that says “80gsm” is a third way of writing it.
When you compare papers, use the full g/m² figure. It is the only unit that does not depend on sheet size.
Grams per square metre
g is a weight in grams. g/m² is the weight of one square metre of the paper — the basis weight, or grammage. “gsm” is the same thing written differently.
80 g/m² means one square metre of this paper weighs 80 grams. Not one A4 sheet, and not the whole pack.
Pounds per ream of a given basis size
Pounds per ream is the weight of a fixed number of sheets at a fixed basis size. You cannot convert it without knowing both the basis sheet size and the sheet count.
The same “80 lb” on a different basis size is a different paper. In the US alone, 80 lb text and 80 lb cover are about 118 and 216 g/m².
| Label | What to confirm |
|---|---|
| g | One sheet, the whole pack, or is “per square metre” simply left out? |
| g/m², gsm | Weight per square metre. Comparable across any sheet size. |
| lb / ream | Which basis sheet size? How many sheets per ream? Text, cover or another grade? |
If a wrapper or a quotation only says “80g”, confirm that the full unit is 80 g/m².
How many gsm is 80 lb?
If it means a 31 × 43 inch sheet at 500 sheets per ream — the convention used by paper merchants in Taiwan — 80 lb is about 84.4 g/m².
A Taiwanese paper merchant’s specification table lists the same sheet size, ream weight and grammage pairs. See the merchant’s table ↗
sheet size 31 × 43 in; 500 sheets per ream.
| Ream weight | Grammage |
|---|---|
| 60 lb / ream | 63.3 g/m² |
| 80 lb / ream | 84.4 g/m² |
| 100 lb / ream | 105.5 g/m² |
These are unit conversions, not a list of papers we stock.
The formula
Grammage (g/m²) = ream weight (g) ÷ [ sheet area (m²) × sheets per ream ]
For 80 lb:
80 × 453.59237 ÷
[ (31 × 0.0254) × (43 × 0.0254) × 500 ]
≈ 84.4 g/m²
Inches to metres, pounds to grams, then divide by area and sheet count.
| Convention | Basis sheet | 80 lb ≈ |
|---|---|---|
| Taiwan ream weight | 31 × 43 in, 500 sheets | 84.4 g/m² |
| US text / book | 25 × 38 in, 500 sheets | 118 g/m² |
| US cover | 20 × 26 in, 500 sheets | 216 g/m² |
Because the basis changes the answer, do not memorise one multiplier and apply it to every paper. A US buyer asking for “80 lb text” and a Taiwanese mill quoting “80 lb” are talking about papers that differ by roughly 30 g/m².
Unit illustration
not 52 lb
Is “52 lb Tomoe River” correct?
If you mean the paper the manufacturer labels 52 g/m² Tomoe River, write the specification as “52 g/m²” or “52 gsm”. Do not rename it “52 lb”.
SAKAE Technical Paper’s product page states 52 g/㎡ explicitly. See the manufacturer’s specification ↗
In conversation, “52g Tomoe River” is fine. In an RFQ, a quotation or a paper confirmation, restore the full unit and confirm the paper name, version and shade at the same time.
This section is about the unit. It does not mean every Tomoe River product has the same grammage, or that every grammage is in stock at all times.
Read more: Tomoe River paper notebooks →Does a higher gsm always mean thicker, better-writing paper?
No. Grammage is a weight specification. It does not guarantee thickness or writing performance.
Different fibres and manufacturing methods give different bulk, so two papers of the same grammage can differ in thickness and hand feel. To predict spine thickness or how thick the finished notebook will be, ask for the paper’s caliper (thickness) data or a physical sample.
| What you want to know | What to look at |
|---|---|
| How heavy the paper is for a given area | Grammage, g/m² |
| How thick the sheet and the book will be | Caliper, page count and binding structure |
| Whether writing shows through from the back | Both sides of a sheet after actual writing |
| Whether ink bleeds through | A test with the pens and inks you intend to use |
| Whether you like the feel | Surface and stiffness of a physical sample |
Touching the paper helps you judge feel. It does not replace the full specification, and it does not replace a writing test.
Ordering custom notebooks: how to state your paper requirement
You do not need to know every printing term. Giving us the points below is far more useful than “a bit thicker” or “80 lb”.
Use and writing instrument
Meeting notes, a yearly planner, or fountain-pen journaling? Mostly ballpoint, gel or fountain pen?
Paper name and grammage
If you have a paper in mind, give the full name and g/m². If not, a photo of the wrapper label works.
Shade and feel
White or cream? Smooth, or with some tooth?
Size and page count
Inside page size and total pages — and confirm whether you count pages or sheets.
What is printed
Ruled, dot grid, dated layouts, or images and solid backgrounds?
A reference sample
If you want to match an existing notebook, a sample tells us more than any pound figure.
A brief that worksWe need corporate meeting notebooks, used mostly with ballpoint and gel pens, cream pages, comfortable for writing on both sides. Wrapper label and photos of our current paper attached — please confirm a suitable paper and grammage.Compare papers: how to choose paper for custom notebooks →
Frequently asked questions
Is 80 lb the same paper as 80 gsm?
Not necessarily. If 80 lb means a 31 × 43 in ream of 500 sheets, it is about 84.4 gsm; on US text basis it is about 118 gsm. 80 gsm simply means 80 grams per square metre.
Does the gsm change when the sheet is cut down to A5?
No. Cutting reduces the weight of each piece, but gsm is weight per unit area, so it stays the same.
Can I judge fountain-pen suitability from gsm alone?
We do not recommend it. Test with the pen and ink you intend to use and check feathering, bleed-through, show-through and drying time.
I do not know what paper we use now. Can I still request a quote?
Yes. Send your current notebook, a photo of the paper wrapper or any known specification, plus how it will be used and what you want to improve. List the unknowns rather than guessing a pound figure.
Choose paper on the full specification first, then on real use.
Pounds need a basis size, gsm is not thickness, and hand feel is not writing performance.
Confirm paper name, grammage, size, page count and writing instrument together, and the paper on your quotation will match the notebook you actually want. Send us your paper label, reference photos and requirements and we will recommend suitable inside-page options.
References
- YT Paper (Taiwan) — ream weight and grammage table
- SAKAE Technical Paper — Tomoe River 52 g/㎡ product specification
Conversions on this page are for understanding units. Actual paper is confirmed against the merchant’s specification and your project details.
Press Release
4.6★ on Google · Trusted Since 1990Real emails from international clients. Real Google reviews from long-term partners. See what 36 years of getting the details right looks like — in their own words.
Read More
Awards of Taiwan Golden PrintPUNDY won awards of Taiwan Golden Print in 2011.
Read More
New Notebook for 2015The business notebook designed by PUNDY is especially made for office users who love simple and fashionable designs.
Read More