Carbonless Paper Weights, Caliper & Tag Grades Explained

Direct answer: Carbonless plies are bond-grade papers specified in pounds of bond basis weight, most commonly 20 lb to 22 lb per ply (roughly 75 to 83 gsm). That is lighter than typical 24 lb letterhead, and it is deliberate: multi-part sets must stay thin enough to feed, fold, and transmit writing pressure through every layer.

What we actually stock: Carbonless Forms runs 21 lb bond, 2-part and 3-part sets only, 8.5″ x 11″ and 8.5″ x 14″. Everything below this line is general industry reference — the weights, grades and part counts different mills and printers offer across the category — not a menu of what we’ll sell you. If you need something outside 21 lb, 2-part or 3-part, call us and we’ll tell you straight whether that’s a job for us.

What “20 lb bond” actually measures

Basis weight is the weight in pounds of one ream, 500 sheets, cut to that grade’s basic size. For bond and writing grades that size is 17 × 22 inches, so 20 lb bond means 500 sheets at 17 × 22 weigh 20 pounds (Iowa DHS Forms Handbook; SEF Inc. glossary; Neenah Paper).

A 17 × 22 sheet cuts into four 8.5 × 11 sheets, which is why a “20 lb” letter sheet does not weigh 20 lb per ream. Because basic size differs by grade, pound figures are not comparable across grades. Grams per square meter is (Neenah):

Carbonless sits at the light end of the bond range, which spans roughly 9 lb to 24 lb (Iowa DHS Handbook).

Real published carbonless weights

Carbonless is not one weight. Each ply grade is often made at a different weight, and mills publish them separately.

**Nekoosa NCR PAPER* Superior** lists 20# CB, 21# CFB, and 20# CF as single uncollated sheets (Nekoosa). Across the line, distributor listings show 20, 20.5, 21, 21.3, 21.4, 21.5, and 22 lb bond (The Paper Mill Store).

Pixelle Trans/rite premium carbonless rolls publish the fullest numbers (Pixelle):

Note the asymmetry. CB grades run to 26 lb and 5.2 mil; CFB grades stop at 21 lb and start as light as 14 lb and 3.0 mil. Middle plies are the ones that multiply, so mills make them lighter. Opacity tracks weight: 14 lb CFB is 76, 26 lb CB is 92.

Caliper: the number that governs feeding

Caliper is thickness in thousandths of an inch, called mils or points (SEF Inc. glossary). It matters more than weight, because caliper is what a feeder, folder, and perforating wheel actually see.

From the Pixelle table, plies land between 3.0 and 5.2 mil. Summing published single-ply calipers for a common 3-part build (20 lb CB at 4.1 + 21 lb CFB at 4.3 + 21 lb CF at 4.1) gives about 12.5 mil. That is an arithmetic sum of published figures, not a quoted set specification; real converted sets vary with grade and mill.

Mills call out “consistent caliper” for a reason (Nekoosa). Variation stacks: three plies each running slightly heavy is a set that jams.

Why a 3-part set is not three times a normal sheet

Two honest clarifications.

Thickness does add up. Three sheets of paper are about three sheets thick. Nothing about the coatings cancels that.

But the usual comparison is wrong in the other direction. People picture “three sheets of the paper in my printer.” Office and letterhead stock is commonly 24 lb bond, 90 gsm; carbonless plies are 20 to 22 lb, with middle plies at 14 to 17 lb. So a 3-part set is thinner and lighter than three sheets of ordinary letterhead, and the gap widens as parts are added.

The mill-side evidence is in M weights, the weight of 1,000 sheets at a given size. For pre-collated 8.5 × 11 NCR PAPER Superior these run 10.3 M for 2-part, 10.5 M for 3-part, 10.7 M for 4-part and 5-part, and 10.8 M for 6-part (Nekoosa/Appvion Carbonless Sheet Training).

Those are per 1,000 sheets, not per 1,000 sets. A 17 × 22 ream cuts four-up, so 1,000 letter sheets equal half a ream at basic size, and 20 lb bond gives an M weight of 10.0 by definition. The published 10.3 to 10.8 range therefore implies an average of roughly 20.6 to 21.6 lb bond per ply across 2- through 6-part collations. That is a derived figure, and it lands where the mill’s published single-sheet weights say it should. The consequence: a 6-part set weighs about the same per sheet as a 2-part set.

What happens to transfer quality as part count rises

Each interface consumes some writing force. The bottom copy of a 6-part set is imaged by whatever pressure survives five layers of paper and five coating interfaces. Manufacturers set guarantees accordingly. Pixelle states its Trans/rite CB gives “immediate image formation” and is guaranteed through five plies (Pixelle). Stock inventory reflects the same ceiling: Nekoosa lists pre-collated Superior sets in 2, 3, 4, 5, and 6 part, with 6-part in a single size and color sequence (Nekoosa).

Three design implications follow:

1. 1. Specify the part count you need, not the maximum. Forms guidance is blunt: challenge each copy and ask what happens if it does not exist (Iowa DHS Handbook).
2. 2. Put the legibility-critical copy high in the stack. The copy going to a customer or a legal file should not be the last ply.
3. 3. Lighter middle plies help pressure reach the bottom. That is what 14 lb and 17 lb CFB grades are for.

Heavier and specialty grades

Not everything in a set has to be bond weight. Nekoosa lists a 105# CF tag in white and manila for sets needing a card-weight bottom ply (Nekoosa). Tag is a separate grade with its own basic size, so 105# tag is nowhere near five times 21# bond in real thickness. This is why gsm and caliper beat pound figures across grades. For high-volume digital work, mills offer heavier grades for laser runnability (Nekoosa Xero/Form II).

FAQ

What weight is carbonless paper? Across the industry, plies are usually 20 to 22 lb bond, about 75 to 83 gsm, with middle plies down to 14 lb and CB up to 26 lb for specific applications (Pixelle; Nekoosa). We stock 21 lb bond exclusively, on every part.

Is carbonless paper thinner than regular copy paper? Per ply, usually yes: office bond is commonly 24 lb / 90 gsm, carbonless plies 20 to 22 lb / 75 to 83 gsm (Neenah; Pixelle).

How thick is a 3-part carbonless set? Adding published single-ply calipers for a typical 20/21/21 lb build gives roughly 12.5 mil. Converted sets vary by grade and mill, so ask for caliper on the specific stock (Pixelle).

How many parts can a carbonless form have? Industry-wide, standard pre-collated stock goes to 6 parts, and at least one mill guarantees the image through 5 plies (Pixelle; Nekoosa). We run 2-part, 3-part, and 4-part collated sets.

Does a 6-part form weigh three times a 2-part form? Roughly, because it has three times the sheets, but it is not heavier per sheet. Published M weights move only from 10.3 to 10.8 from 2-part to 6-part (Nekoosa/Appvion).

What does caliper mean on a paper spec? Thickness measured in thousandths of an inch, also called mils or points (SEF Inc. glossary).

Why do carbonless colors go white, canary, pink, goldenrod? A distribution convention, so each department can grab its copy by color. Standard sequences include white/canary, white/canary/pink, and goldenrod/pink/canary/white (Nekoosa); colored copies are standard advice where copies are sorted and routed at one point (Iowa DHS Handbook).

Can I get a heavier bottom sheet? Elsewhere in the industry, yes — 105# CF tag stock is a standard mill offering for sets that need a card-weight final ply (Nekoosa). We don’t stock it; every job we run is 21 lb bond.

Sources

• Pixelle Specialty Solutions, Premium Carbonless Rolls sell sheet — https://www.pixelle.com/hubfs/5066686/_sell_sheets/SellSheet_Carbonless-Rolls.pdf
• Nekoosa, NCR PAPER* Superior Carbonless — https://nekoosa.com/products/ncr-paper-superior-carbonless
• Nekoosa, NCR PAPER* Xero/Form II Carbonless — https://nekoosa.com/products/ncr-paper-xeroformr-ii-carbonless
• Nekoosa / Appvion, Carbonless Sheet Training —
• The Paper Mill Store, NCR Paper* Brand Superior — https://www.thepapermillstore.com/paper-mills/nekoosa/ncr-paper-brand-superior
• Neenah Paper, Paper Basis Weights — https://www.neenahpaper.com/resources/paper-101/basis-weights
• Iowa Dept. of Human Services, Forms Analysis and Design Handbook — https://hhs.iowa.gov/media/6488/download?inline
• SEF Inc., Glossary of Terms — https://www.seforms.com/resources/glossary.html