What Is 100 lb Cardstock? | The Complete Breakdown

100 lb cardstock is a heavy paper stock where 500 sheets at its standard reference size weigh 100 pounds, equating to roughly 270 gsm of rigid, premium material.

For the full breakdown, see our best 100 Lb Cardstock guide.

If you’ve ever ordered paper online and hesitated at “100 lb cover,” you’re not alone. This weight class is a favorite for business cards, thick postcards, and invitations because it balances stiffness with the ability to run through a standard printer. But there’s a twist: that “100 lb” label doesn’t tell the full story. The paper’s class—cover versus text—changes everything about its thickness and feel, so understanding what you’re buying before you hit “add to cart” saves a wasted order.

To cut through the confusion, this guide explains how basis weight works, what 100 lb cover actually means in practice, and how to choose the right cardstock for your next print project—with a practical buying resource for those ready to compare options.

How Paper Weight And “100 lb” Are Measured

Basis weight is a North American system that measures how much 500 sheets of paper weigh at the paper’s standard reference size. The trick is that each paper category uses a different standard sheet size, which means “100 lb” isn’t a universal measurement of thickness.

For cardstock, when a listing says 100 lb cover, it means 500 sheets of the paper at its reference size weigh exactly 100 pounds—but that size is different from the one used for text stock. Per industry reference guides, 100 lb cover translates to approximately 270 gsm, which is notably heavier and stiffer than its text counterpart. The gsm (grams per square meter) figure matters more than the pound number because it gives you an apples-to-apples metric across different paper lines. When comparing two products, the single most reliable check is to verify the gsm value alongside the “cover” or “text” class label.

100 lb Cover Versus 100 lb Text Stock

This is the source of the most common ordering mistakes. A 100 lb text stock is thinner and more flexible than a 100 lb cover stock, even though the pound number is identical. Because basis-weight tables use different standard sheet sizes for different categories, the same number can represent vastly different paper thicknesses depending on whether the class is text, cover, or index.

The practical takeaway is straightforward: when a project calls for rigid, sturdy pieces like a premium business card or a postcard that won’t bend in the mail, you want 100 lb cover. If you need paper that folds cleanly for a multi-page brochure cover, a lighter cover weight often works better because it creases without cracking. Treating the weight class as part of the product name—not just the number—prevents the frustrating experience of receiving paper far thinner than you expected.

Best Uses And Printing Considerations For 100 lb Cardstock

This weight class is the default professional pick for single-sheet items that need to feel substantial. Standard uses cited across printing references include business cards, postcards, invitations, brochure covers, flyers, signs, and greeting cards. In nearly every case, the stock’s rigidity signals quality and durability—qualities that matter for pieces meant to be handled or shipped.

On the compatibility side, cardstock in this range is generally suited for both inkjet and laser printers, but printer support depends on the device’s paper path rather than the weight alone. Lexmark’s media guidance highlights that each printer has specific supported media types and weight limits—some require a manual-feed path for heavy stock to avoid jams. The checklist before loading your tray should be:

• Check the official printer manual for the maximum media weight, measured in lb or gsm.
• Verify whether the printer requires a manual-feed or rear-paper-path slot for thick media.
• Test a single sheet first; if it jams, switch to the other paper path rather than forcing the stock.

When the goal is a folded piece like a greeting card, choose your grain direction carefully—folding along the grain yields a cleaner crease and less cracking on the cover stock surface.

Choosing The Right Cardstock For Your Project

Selecting cardstock comes down to matching the stock density to the physical demands of your finished piece. Lighter cover weights work fine for multi-page covers or pieces that need to fold; the 100 lb cover class earns its place for sturdier single-sheet items like business cards that will be handled repeatedly or postcards that travel through the mail system without a protective envelope.

Whenever you’re comparing listings online, resist the urge to rely on the “100 lb” label alone and instead:

• Look for the basis-weight class—cover versus text—clearly stated in the product title or specs.
• Check for the metric equivalent, usually listed as gsm; 270 gsm or a nearby value confirms you’re looking at cover stock.
• Feel the paper when possible through a sample pack; thickness perception varies across brands even at the same nominal weight.

One additional distinction worth noting is the difference between “cover” and “index” stock classes. An index-class paper labeled 100 lb has a different standard sheet size than a cover-class stock with the same number, meaning the physical feel and stiffness can differ noticeably. Reading the full product specification is always safer than assuming two “100 lb” papers from different lines are interchangeable.

If you’re evaluating specific products for purchase, our tested roundup covers the top-rated options and what makes each one worth considering for different print jobs—a fast way to compare real-world picks side by side.

For most home and small-business printing, 100 lb cover cardstock offers a sweet spot: it’s heavy enough to read as premium, light enough to run through an average laser or inkjet printer without specialized equipment, and stiff enough for any single-sheet piece you can imagine.

Before you buy, double-check the product listing for the weight class and the gsm conversion rather than the pound number alone. That one habit eliminates the vast majority of wrong-stock orders—and keeps your business cards looking sharp, your postcards stiff in the mailbox, and your wedding invitations feeling worth every stamp.

Note: This guide is for informational purposes. Always verify your specific printer’s media specifications with the official manual before loading heavy cardstock.