Cardstock is a heavier, stiffer paper commonly used for thank-you cards, packaging inserts, postcards, business cards, covers, and other printed pieces that need more structure than regular paper.
However, cardstock is not one fixed material. Different stocks can vary in GSM, basis weight, caliper, stiffness, coating, texture, and fiber composition. Two sheets with a similar paper weight may still differ in thickness and feel, while coated, uncoated, kraft, recycled, and specialty stocks can produce different printing and finishing results.
For buyers, the most useful way to compare cardstock is to look beyond GSM alone. Weight, thickness, surface, print behavior, finishing compatibility, and the way the finished card will be used all affect material selection.
This guide explains what cardstock is, how cardstock weight and thickness are measured, the most common cardstock types and weight ranges, and how to choose a suitable stock for thank-you cards, packaging inserts, and other branded printed cards.
What Is Cardstock?
Cardstock is a relatively heavy paper with more body and rigidity than ordinary writing or text paper. In commercial printing, the term cover stock is also commonly used for papers in this general category.
It is not one single paper specification. Different stocks can vary in weight, thickness, surface, color, coating, texture, and fiber composition, which means two papers both described as cardstock can produce noticeably different finished results.
Depending on the paper category, manufacturer, and market, heavier printing papers may also be described as cover, bristol, index, or specialty stock. These terms are related, but they do not all refer to exactly the same material specification. For this reason, cardstock is best understood as a broad category of heavier printing paper rather than one fixed type of paper.
How Are Cardstock Weight and Thickness Measured?
Three terms are particularly useful when comparing cardstock: GSM, basis weight, and caliper. GSM and basis weight describe paper weight, while caliper describes the actual thickness of the sheet.
GSM
GSM stands for grams per square meter. It tells you how much one square meter of paper weighs.
Because GSM always uses the same one-square-meter area, it allows the paper weight itself to be compared across different paper categories, products, suppliers, and markets. For example, a 300 gsm stock has more mass per square meter than a 250 gsm stock.
However, a higher GSM does not necessarily mean a thicker sheet. GSM measures weight per square meter, while actual thickness depends on the paper’s density, fiber structure, coating, and construction. For example, a dense 350 gsm coated stock can sometimes have a similar or even lower caliper than a bulkier 300 gsm uncoated stock.
Pound / Basis Weight
In the U.S., paper is also commonly specified in pounds, such as 80 lb cover or 100 lb cover. This system is known as basis weight.
Basis weight refers to the weight of a 500-sheet ream of paper cut to the standard basic size for that paper category. The important point is that the basic sheet size is not the same for every category of paper. For example, 80 lb text and 80 lb cover do not represent the same paper weight, so the pound value only makes sense when the paper category is known.
Caliper
Domtar defines caliper as the thickness of a sheet of paper. Depending on the market and supplier, it may be expressed in points, mils, microns, or millimeters.
Caliper becomes particularly important when a card must fit within an existing packaging structure. For example, it may need to slide between a product and an insert, fit beneath a carton flap, or pass through automated packing equipment.
In these situations, knowing only that a stock is “350 gsm” may not be enough, because GSM describes weight rather than exact thickness. This is why paper manufacturers commonly list GSM and caliper as separate specifications.
Common Cardstock Weight Ranges
There is no single cardstock weight that is right for every application. GSM can provide a useful starting point, but the final choice should also consider the stock’s actual thickness, stiffness, surface, and intended use.
| Cardstock Weight | Common CNN Package Applications |
|---|---|
| Below 250 gsm | Lightweight information inserts |
| Around 250 gsm | Instruction cards and packaging inserts |
| Around 300–350 gsm | Thank-you cards and branded inserts |
| 400 gsm and above | Specialty cards where the actual thickness and packaging fit have been checked |
In CNN Package projects, 250–350 gsm is a common range for thank-you cards and packaging inserts. Around 250 gsm is often used for lighter information cards, while 300–350 gsm is commonly selected for thank-you cards and branded inserts.
These ranges describe common production choices rather than fixed rules about thickness or stiffness. A higher GSM means more paper mass per square meter, but it does not guarantee that the stock will be proportionally thicker or more rigid.
This distinction becomes especially important with heavier stocks. In one CNN Package project, a customer selected a 400 gsm card before the available space inside the folding carton had been fully checked. The actual caliper of the selected stock reduced the available clearance, making manual insertion more difficult and creating problems during automated packing.
For this reason, cardstock weight and actual thickness should be checked together when the card needs to fit inside an existing carton or mailer. The GSM range can help narrow the options, but the final stock should be evaluated based on the specific material and how it will be used.
Common Types of Cardstock
Coated Cardstock
Coated cardstock has a treated surface designed to create a smoother printing face. It is a common choice for cards with photography, strong color coverage, detailed graphics, or a polished commercial appearance. In CNN Package’s custom-card projects, coated papers are the most frequently selected option.
Uncoated Cardstock
Uncoated cardstock has a more natural paper surface and is often selected for minimal, tactile, or writing-focused designs.
CNN Package had one insert-card project in which the customer initially chose coated stock but later decided customer-service staff needed to handwrite personal messages on each card. The coated surface did not suit the handwriting requirement, so CNN Package recommended changing to uncoated cardstock. The resulting surface gave the ink a more practical writing surface and reduced the risk of smeared handwritten messages.
This is a good example of why end use should be confirmed before stock selection.
Kraft Cardstock
Kraft cardstock is commonly selected for its natural brown appearance and distinctive paper texture.
Because the substrate itself is brown rather than bright white, printed colors can appear different from the same artwork reproduced on white cardstock. Light colors, subtle tones, and detailed photographic images may lose contrast or shift in appearance depending on the printing method and ink coverage.
For this reason, artwork intended for kraft cardstock may need to be adjusted to account for the color of the paper itself.
Recycled Cardstock
Recycled cardstock contains recycled fiber, but the percentage and source can vary from one stock to another. It may be coated or uncoated and is available in a range of colors and surface finishes.
If recycled content is an important part of the material specification, ask the supplier for the relevant product specifications or supporting documentation. A paper described as “natural” or “kraft” should not be assumed to contain a specific percentage of recycled fiber.
Textured or Specialty Cardstock
Textured and specialty cardstocks are chosen when the surface itself is intended to contribute to the visual or tactile character of the finished card.
Common options include felt-marked, linen-like, rough, embossed, pearlescent, colored, and other distinctive paper surfaces. Because texture and surface treatment can affect print reproduction and finishing results, the specific stock should be checked against the intended artwork and finishing before production.
What Is Cardstock Used For?
Cardstock is commonly used for printed pieces that need more structure than ordinary paper, especially when the piece is handled on its own rather than as part of a multi-page document.
Thank-You Cards
Cardstock is widely used for thank-you cards included with ecommerce orders, gift packaging, and branded product shipments. These cards may carry a short message, brand story, discount code, social media information, or other customer-facing content.
For custom thank-you cards, the stock can be selected to coaordinate with the rest of the packaging.
Information Cards
Cardstock is also commonly used for cards that provide practical information inside a package. These may include instruction cards, care guides, product information cards, usage notes, or QR-code cards that direct customers to additional content.
Other Printed Cards
Beyond packaging applications, cardstock is also used for postcards, business cards, membership cards, referral cards, promotional cards, and other standalone printed pieces that need more body than regular paper.
How Cardstock Affects Printing and Finishing
The cardstock itself influences both how artwork is reproduced and how later finishing processes perform.
Surface characteristics are especially important for printing. Smooth coated stocks generally reproduce solid colors, fine details, and photographic images differently from more absorbent uncoated or textured papers. Kraft and colored stocks can also alter the appearance of printed colors because the paper itself becomes part of the final visual result.
The same principle applies to finishing. Foil stamping, Spot UV, embossing, debossing, and lamination can all behave differently depending on the paper surface, thickness, and construction.
For example, foil may appear cleaner on a smooth stock than on a heavily textured surface, while embossing requires enough material structure to create the intended relief. Lamination can also change both the surface feel and the final thickness of the card.
CNN Package has produced multi-component packaging projects in which cards, folding cartons, and mailers shared the same black-and-foil visual direction. In projects like these, coordinating the stock and finishing across components helps create a more consistent final presentation.
Common Cardstock Buying Mistakes
- Choosing by GSM alone. GSM is useful for comparing paper weight, but it does not tell you the exact thickness, stiffness, surface feel, or finishing performance of a specific stock.
- Comparing pound weights without checking the paper category. The same pound number does not mean the same GSM across paper categories. For example, 80 lb text and 80 lb cover use different basic sheet sizes, so they represent different weights per unit area.
- Ignoring how the card will be used after printing. A coated or heavily treated surface may not be suitable if handwritten notes or signatures are required.
- Forgetting to check packaging fit. A heavier stock may be unnecessary if the finished card takes up too much space inside a carton or creates problems during packing.
When the final feel, thickness, or surface is important, reviewing a physical paper sample is often more useful than relying on specifications alone.
What to Tell Your Card Printing Supplier
When requesting a quote for custom printed cards, give your supplier enough information to understand both the card itself and how it will be used.
Useful details include:
- finished card size,
- quantity,
- single- or double-sided printing,
- preferred cardstock or desired feel,
- whether the card needs to be written on,
- required finishes such as foil, Spot UV, embossing, lamination, or rounded corners,
- the packaging the card will be placed inside,
- and any reference sample you would like the supplier to match.
If you already have a physical card with the thickness, stiffness, or surface feel you want, sending that sample can be more useful than simply asking for “the same GSM.”
The final cardstock choice should be based on the complete specification—not paper weight alone. Weight, caliper, surface, printing, finishing, and packaging fit all contribute to how the finished card performs.
