Honeycomb paper GSM vs US pounds: a conversion chart
Convert honeycomb paper GSM to US basis weight pounds and back, with a chart from 50 to 120 GSM, the formula, and the ream-size traps on US spec sheets.
A US spec sheet lands on your desk. It says "50# natural kraft". Your supplier in India or Europe quotes "80 GSM". Are they the same paper?
Nearly. US paper weight (basis weight) for kraft is the weight in pounds of a ream of 500 sheets of 24 x 36 inches, which is 3,000 square feet. To convert, multiply GSM by 0.614 to get pounds, or multiply pounds by 1.628 to get GSM. So 80 GSM is about 49#, and in the trade it is sold as 50#.
We make honeycomb paper in inch widths for US buyers, so our team has to speak both units. Here is the chart we use, and the traps I would warn any buyer about.
The conversion chart, 50 to 120 GSM
The pounds below are on the 3,000 sq ft basis, the one used for kraft and other packaging papers.
| GSM | US basis weight (lb per 3,000 sq ft) | How it is usually described |
|---|---|---|
| 50 | 30.7 | 30# |
| 55 | 33.8 | 34# |
| 60 | 36.9 | 37# |
| 65 | 39.9 | 40# |
| 70 | 43.0 | 43# |
| 75 | 46.1 | 46# |
| 80 | 49.2 | 50# in trade use |
| 85 | 52.2 | 52# |
| 90 | 55.3 | 55# |
| 100 | 61.4 | 60# |
| 110 | 67.6 | 68# |
| 120 | 73.7 | 74# |
And the other way, for buyers who start from a US figure:
| US basis weight | GSM (approx.) |
|---|---|
| 30# | 48.8 |
| 35# | 57.0 |
| 40# | 65.1 |
| 45# | 73.2 |
| 50# | 81.4 |
| 60# | 97.7 |
| 70# | 113.9 |
| 75# | 122.1 |
Round figures sell paper. Exact figures settle disputes. If your quality team checks weight on arrival, put the exact GSM on the purchase order, not just the rounded pound figure.
Where does 0.614 come from?
It is plain arithmetic, and I like buyers to see it, because then nobody can confuse them.
- A 24 x 36 inch sheet is 6 square feet. A ream of 500 sheets is 3,000 square feet.
- 3,000 square feet is 278.7 square metres.
- One pound is 453.6 grams.
- So one pound per ream is 453.6 ÷ 278.7 = 1.6275 grams per square metre.
- Pounds = GSM ÷ 1.6275, which is GSM × 0.6144.
The basis sizes come from the US system of ream sizes. Wikipedia's Grammage article lists them, with 24 x 36 inches and 500 sheets for newsprint, bag and other packaging papers. As the article explains, packaging paper inherited the newsprint ream because the first paper bags and wrapping papers were made from newsprint.
Which ream-size traps catch buyers?
The pound figure means nothing until you know which ream it refers to. The same paper can be "20 lb" on one basis and "49 lb" on another.
| Paper type | US basis size | Sheets | Area | 80 GSM in pounds |
|---|---|---|---|---|
| Kraft, bag, wrapping | 24 x 36 in | 500 | 3,000 sq ft | 49.2# |
| Bond, writing (office paper) | 17 x 22 in | 500 | about 1,300 sq ft | 21.3# |
| Book, text, offset | 25 x 38 in | 500 | about 3,300 sq ft | 54.0# |
| Tissue | 24 x 36 in | 480 | 2,880 sq ft | 47.2# |
Three practical warnings come out of this table.
- Office paper is sold on the bond basis. So the "20 lb copy paper" in your printer is about 75 GSM, almost the same weight as a 46# kraft. Nobody should compare the two numbers directly.
- Tissue uses a ream of 480 sheets, not 500. If you buy a tissue interleaf to run with honeycomb, a "10 lb tissue" is about 17 GSM. Convert tissue with 1.695, not 1.628.
- Paperboard uses a different basis again (1,000 sheets of 12 x 12 inches, i.e. pounds per 1,000 square feet). Never mix a carton specification into a paper conversion.
A worked example from a US spec sheet
Picture a packaging distributor in Texas who sends this line for a quote: "Honeycomb wrap, 15 in x 820 ft, 50# natural kraft."
Here is how I would read it.
- 15 inches is 381 mm. We quote it as a 15" roll, made to the inch, not as our 380 mm metric width.
- 820 feet is 250 metres. That matches our standard 250 m flat trade roll.
- 50# is about 81 GSM, so our 80 GSM grade is the match. It is 49.2# on paper, sold as 50#.
- One question is still open. Is the 820 feet flat or expanded? The spec does not say, and that one word changes the value of the roll. Our guide to 12, 15 and 20 inch rolls covers this trap in detail.
I would answer that buyer with both units on the quote: 15" (381 mm) x 820 ft (250 m) flat, 80 GSM (50#). Nobody has to convert anything twice.
Does basis weight tell you thickness?
No. Basis weight and GSM both measure weight per area. Thickness is called caliper, and US sheets give it in mils or points (a thousandth of an inch).
Two kraft papers of the same weight can have different calipers. Fibre, pressing and moisture all play a part. For honeycomb wrap, I would specify by weight, because weight is what you can check with a cheap scale on your own desk. Cut a 10 cm square, weigh it and multiply by 100, as our bulk purchase order guide shows.
If you only have pounds and a US-made scale, cut a 12 x 12 inch square instead. That is one square foot, or 1/3,000 of a ream. Weigh it in grams, multiply by 3,000, and divide by 453.6. The answer is the basis weight in pounds.
Moisture changes the weight
Paper takes water from the air. A damp sample weighs more and reads heavier in both GSM and pounds. Test labs condition paper at 23 °C and 50% relative humidity before they weigh it, the standard atmosphere in ISO 187:2022, so do your check in a dry, air-conditioned room, not on a humid loading dock.
We control moisture in our own plant for the same reason. A grade is only a grade if it is measured the same way at both ends.
Where we fit
We make honeycomb paper from 50 to 120 GSM, which is roughly 30# to 74# on the US basis. The inch widths for the US are 12", 15" and 20", and other widths are made to order. Every lot is checked for GSM before it is packed. You can see the full range on our products page.
One honest limit. Our paper is specified and tested in GSM. If your contract is written only in pounds, I would ask you to add the GSM figure too, so both our quality teams measure the same thing.
Send us your US spec sheet through the contact page, and we will send back the metric version, line by line, with a sample to match.
Questions buyers ask
Is 50 lb kraft paper the same as 80 GSM?
Close, but not exactly. 50# on the 3,000 sq ft basis is about 81 GSM, and 80 GSM is about 49#. In the trade, 80 GSM paper is normally sold as 50#. If your spec has a tight weight tolerance, write the GSM figure on the order as well.
Why does my supplier quote GSM when I asked for pounds?
Because most of the world outside North America sells paper by GSM, and mills test it that way. Ask for both figures on the quote. A supplier who can convert without hesitation usually understands the US market.
Is heavier basis weight always better for honeycomb wrap?
No. A heavier sheet makes stiffer cells and tears less, but it costs more per foot and folds less closely around small items. Pick the weight by testing on your products. Our GSM guide explains how.
Can I convert caliper in mils or points to GSM?
Not reliably. Caliper is thickness, and GSM is weight per area. Two papers of the same weight can differ in thickness. If a spec gives only caliper, ask for the basis weight too.
