Posterboard: Types, Sizes, and Campaign Uses Explained

Most people use the word “posterboard” to mean any rigid or semi-rigid surface used to display printed content. In practice, the term covers a range of substrates with very different properties, different ideal use cases, and very different price points. We work with posterboard in all its forms, from thin card stock sheets at local print shops to corrugated plastic panels installed along parade routes to foam core boards that front retail activations and pop-up events.

Getting posterboard wrong costs time and money. Use a substrate that is too thin for an outdoor installation and you have warped, buckled display pieces within hours of the first dew. Use a substrate that is overbuilt for a one-day indoor event and you have paid three times more than necessary. This guide covers every major posterboard type, its standard sizes and measurements, and the specific campaign contexts where each one delivers the best result.

What Is Posterboard?

Posterboard is a category of display substrate, a flat, rigid or semi-rigid material used as the carrier for printed graphics, hand-lettered messaging, or photographic print. The term is used broadly to describe anything from a 22×28 inch sheet of white card stock bought at an art supply store to a 4×8 foot sheet of corrugated plastic used for directional signage at a large outdoor event.

In professional print and campaign contexts, posterboard is distinct from paper posters. A paper poster is printed, rolled or flat-packed, and either pasted or pinned to a wall. A posterboard piece is self-supporting, typically thicker, and either mounted on a stand, placed on a ledge, or held by a presenter. The distinction matters because the design, production method, and installation approach differ significantly between the two.

We use posterboard as a campaign element in four main ways: freestanding event signage, held signage (by street teams or brand ambassadors), point-of-purchase retail display, and framed or mounted window graphics. Each use case has a preferred substrate type and a preferred size range.

Standard Posterboard Sizes

The sizes below represent the most commonly stocked posterboard dimensions. These are the formats that printers, sign vendors, and retail suppliers carry as standard stock. Custom sizes are available from any wide-format shop, but these are the ones that produce the lowest per-unit cost when ordered in quantity.

The 22×28: The Retail Standard

The 22×28 inch (55.9 x 71.1 cm) format is so embedded in US retail fixture design that entire generations of floor stand and snap-frame systems were built to hold it. If you walk into any national retail chain and look at their promotional display frames, the vast majority are sized for a 22×28 insert. When we run retail activation campaigns that need to integrate with existing fixture systems, this is the format we confirm first. At roughly 4:5 aspect ratio, it is wide enough for a strong visual and tall enough for a clear hierarchy of headline, visual, and call-to-action.

The 18×24: The Street Team Standard

When we brief street teams to carry signs, 18×24 (45.7 x 61.0 cm) is the default. It is large enough to read from ten to fifteen feet, light enough to hold comfortably for hours, and rigid enough (on foam core or a double-layer card stock mount) to stay flat even in moderate wind. We have run campaigns where a team of twenty people spread across a half-mile corridor, each carrying an 18×24 posterboard. The visual repetition at that scale works like a series of outdoor placements but with mobile, human infrastructure.

Types of Posterboard Materials

The word “posterboard” technically describes a material as well as a category. Here is how the main posterboard types break down by material, thickness, and appropriate use case.

Card Stock Posterboard (Paper-Based)

This is what most people picture when they hear the word “posterboard”: a thick, smooth paper sheet, usually white on both sides, with a slightly waxy or coated surface. It is the kind sold in pads at art supply stores and used for school projects, hand-lettered signs, and low-cost event signage.

Standard card stock posterboard weights range from 65 lb (lightweight, flexible) to 110 lb (semi-rigid, holds its shape better). For professional print use, posterboard card stock is typically available in 14 pt (about 0.014 inches thick, or 0.36 mm) to 24 pt (about 0.024 inches thick, or 0.61 mm). A 22×28 sheet of 18 pt card stock posterboard is stiff enough to stand in a frame without buckling and light enough to mount on a foam core backing if more rigidity is needed.

Card stock posterboard is the correct choice for: budget event campaigns with short lifespans, interior retail displays, handout boards for street teams in low-wind conditions, and any application where the piece will be displayed for less than 48 hours. It is not the right choice for outdoor multi-day campaigns where weather is a factor.

Foam Core (Foam Board)

Foam core is a sandwich construction: two thin paper or clay-coated paper faces bonded to a foam center. The standard thickness for most professional applications is 3/16 inch (about 4.8 mm). A 5mm version is also common in metric-system countries. Heavier-duty foam core runs at 1/2 inch (about 12.7 mm) for large-format display pieces that need to stand free or resist bending.

Foam core posterboard prints beautifully because its surface is the same clay-coated paper used in standard print applications. We use it for mounted event displays, photo gallery-style installations, retail window mounts, and any interior application where we need a flat, rigid surface with clean edges. Foam core is not appropriate for outdoor or wet environments, moisture softens the foam core and causes the face paper to delaminate.

For street campaigns and outdoor events, we often use foam core in a covered or sheltered context: under a tent canopy at an activation, inside a retail window where it stays dry, or on a table display inside a venue. The moment it is exposed to rain or high humidity for an extended period, it fails.

Corrugated Plastic (Coroplast)

Corrugated plastic, known by the brand name Coroplast and sometimes called “corriboard” or “fluted plastic,” is the outdoor standard for posterboard applications that need to survive weather. The material is made of twin-wall polypropylene: two flat polypropylene sheets connected by a series of parallel internal ribs, creating the familiar fluted cross-section.

Standard corrugated plastic posterboard thicknesses for campaign use are 4mm (about 5/32 inch) for standard outdoor signage and 6mm (about 1/4 inch) for larger or longer-duration installations. The material is UV-resistant, water-resistant, and can withstand temperatures from well below freezing to direct sun without warping. We use corrugated plastic for outdoor event directionals, A-frame inserts that face the street, yard-style signage for promotional campaigns, and temporary wayfinding systems.

The printing limitation of corrugated plastic is that the surface does not absorb ink the way paper does. Direct printing on coroplast requires UV-cured inkjet printing with ink specifically formulated for polyolefin surfaces. Alternatively, and very commonly in street marketing, we print on adhesive-backed vinyl or paper and apply it to the coroplast substrate. This gives us the full range of print quality available from paper printing while leveraging the structural durability of the coroplast panel.

PVC Foam Board (Sintra)

PVC foam board, sold under trade names including Sintra and Komatex, is a rigid, lightweight expanded PVC sheet. Unlike Coroplast, which has an internal rib structure, PVC foam board is a solid, homogeneous material throughout. This gives it a smooth, flat surface on both faces that takes both direct digital printing and applied vinyl graphics extremely well.

Standard thicknesses for PVC foam board in campaign applications are 3mm (about 1/8 inch) for lightweight interior applications and 6mm (about 1/4 inch) for heavier display pieces and outdoor use. PVC foam board is more expensive than corrugated plastic but delivers a more finished, professional look. We use it for high-end retail activations, permanent-style event installations, and branded display systems that will be used repeatedly across multiple activations.

At 6mm, a 24×36 PVC foam board panel is rigid enough to stand free in a lightweight floor stand, does not flex in mild wind, and can be routed or die-cut cleanly for shaped displays. It is also machinable, we have had campaign display pieces routed into the shape of a product or logo, then printed and assembled into three-dimensional display structures.

Gatorboard

Gatorboard is a premium foam board variant with rigid fiberglass or polystyrene faces instead of the paper faces used in standard foam core. It is heavier than standard foam core but significantly more durable, it does not dent as easily, resists moisture better, and holds up to repeated handling. It is the right choice for display pieces that will be reused across multiple events or that need to maintain a pristine surface appearance across an extended installation period.

We use Gatorboard for high-end lobby displays, photographic print mounts for gallery-style events, and brand ambassador boards that will be carried by hand at multiple events over a campaign period. It costs roughly two to three times the price of standard foam core for equivalent dimensions but lasts many times longer in active use.

Posterboard Weight and Thickness: What the Numbers Mean

Posterboard weight is measured in two systems depending on the material. Paper-based posterboard uses the pound (lb) system or the point (pt) system. Board-format substrates (foam core, coroplast, PVC) use metric thickness (mm) or imperial thickness (inches).

Posterboard in Street Marketing Campaigns

We have run more posterboard-based street campaigns than we can count. The format is flexible, fast, and affordable at the quantities needed for citywide activations. Here is how posterboard shows up in our street campaign toolkit.

Street Team Held Signage

A street team of twenty to thirty people, each carrying an 18×24 foam core posterboard printed with a campaign message, creates a roving out-of-home impression at scale. The key is weight and durability. We print on 3/16 inch foam core for this application: light enough to hold for a four-hour activation shift without fatigue, rigid enough to stay flat and readable when the person is moving. For campaigns in humid or rain-risk conditions, we laminate the printed surface with a matte or gloss film that seals the print against moisture.

Design considerations for held street team boards are different from fixed-location posters. The headline needs to be shorter and larger, three to five words maximum, set at a size that reads from twenty feet. The background needs to be a solid block of high-contrast color rather than a detailed photograph, because the board is moving and the viewer has less than one second to register the message. We typically run the brand logo at thirty to forty percent of the board’s height so it dominates the visual field.

A-Frame and Sidewalk Signage

A-frame sidewalk signs are one of the workhorses of local business and event marketing. The standard A-frame hardware holds either a 22×28 or a 24×36 insert, depending on the model. We supply 4mm corrugated plastic inserts in these sizes for clients who need the outdoor durability but want to swap creative quickly between campaign phases. Coroplast inserts can be printed in full color at a per-unit cost low enough that replacing them for a new message or a new promotion cycle is affordable at any campaign scale.

Event Directional Signage

Outdoor events, street fairs, pop-up activations, brand-sponsored gatherings, always need directional signage. We build these systems on corrugated plastic: 4mm for most directional arrow boards, 6mm for anchor signs at key decision points like parking entrances and main entry gates. Standard sizes for directionals are 18×24 for arrow signs mounted on wooden stakes or metal H-stakes, and 24×36 for anchor information boards. We print them in the event’s brand colors with simple, high-contrast text and arrows.

Guerrilla Pop-Up Displays

Pop-up retail and guerrilla brand activations often need a display system that can be set up in minutes, requires no tools, and looks professional enough to represent the brand properly. We build these systems from PVC foam board or Gatorboard panels in 24×36 or 30×40 sizes, connected with photo-quality graphics printed on adhesive vinyl or direct UV print on the board surface. The panels can clip into lightweight aluminum frames, lean against walls, or stand on easels depending on the space. At the end of the activation, they pack flat into a cargo van and are ready for the next location.

How Posterboard Performs in Outdoor vs. Indoor Settings

The single most common mistake clients make with posterboard is choosing an indoor substrate for an outdoor application. Here is a clear breakdown of which materials belong where.

Printing on Posterboard: Methods and Specs

Not all posterboard materials accept all print methods. Here is a quick guide to matching your print process to your substrate.

Card Stock Posterboard

Card stock posterboard prints on offset lithography presses, digital offset (HP Indigo, Xerox iGen), and wide-format inkjet. For quantity runs, 500 pieces or more, offset delivers the best cost per unit. For shorter runs, digital offset or inkjet is more economical. File requirements: CMYK, 300 DPI at final size, with 1/8 inch bleed on all sides.

Foam Core

Foam core is almost always printed by applying a separate paper or vinyl print to the board face rather than printing directly on the foam core itself. The print piece, usually produced on a wide-format inkjet, is adhered to the foam core face using spray mount, dry mount heat press, or pressure-sensitive adhesive. The result is a flat, smooth face with full photographic print quality. The alternative is direct UV printing on foam core, available from large sign shops, which eliminates the mounting step and delivers a clean result but at a higher per-unit cost.

Corrugated Plastic

Corrugated plastic accepts direct UV inkjet printing at most sign shops. This method uses UV-cured inks that bond to the polypropylene surface and produce durable, weatherproof output. For high-resolution photographic content, we prefer printing on adhesive vinyl and applying to the coroplast rather than direct UV print, because the vinyl surface holds finer detail better. Color profile: CMYK or RGB depending on the vendor’s print workflow, confirm before submitting. Resolution: 100 to 150 DPI at final size for most outdoor directional uses, 200 DPI for close-viewing retail applications.

PVC Foam Board and Gatorboard

Both PVC foam board and Gatorboard accept direct UV printing and applied vinyl equally well. Direct UV is preferred for flat, single-piece displays; applied vinyl is preferred when the display piece has complex shapes, routed edges, or when the print will wrap around edges. For premium activations, we use a matte laminate over the UV print to reduce glare and give the piece a high-end look that reads well under both natural and artificial light.

Posterboard vs. Paper Posters: When to Use Each

Clients new to print campaigns sometimes wonder why they would ever choose a heavier, more expensive posterboard over a standard paper poster. The answer depends entirely on the application.

Paper posters are the right choice for: high-quantity street paste-up campaigns, transit placements, any application where the poster is adhered to a wall or surface and becomes part of that surface. Paper posters can be printed in the thousands at very low per-unit costs, and for paste-up applications the paper format is actually necessary, rigid boards do not paste-up.

Posterboard is the right choice for: any application where the display piece needs to stand free, be held by a person, be moved between locations, or survive multi-day outdoor installation without adhering to a surface. Posterboard is also the right choice for any premium event context where paper would look cheap or temporary and the client needs the display to communicate quality.

We often run campaigns that use both at the same time: a paper poster street campaign builds awareness across the city, while foam core or PVC boards at the event itself create the immersive on-site brand environment. The paper does the reach; the board does the experience.

Custom Posterboard Sizes for Specialty Applications

While the standard sizes cover most campaign needs, we regularly produce custom posterboard pieces for applications that do not fit a standard format. Common custom sizes include:

• Backlit display panels: Custom-sized to fit the specific light box frame at a venue or retail location. We measure the frame interior first, then produce the board to fit precisely with no gap at the edges.
• Cutout silhouettes: Die-cut or router-cut to the shape of a product, character, or logo. These are typically PVC foam board or Gatorboard, 6mm thick, with UV-printed graphics. Used for brand activations, photo opportunity installations, and retail window displays.
• Counter cards and easel backs: Custom-sized from 5×7 to 14×18 depending on the counter space available, with an easel back die-cut into the card itself so no separate stand is needed.
• Floor graphics on rigid substrate: Printed on anti-slip laminated PVC board, typically 24×36 or custom-cut, for branded floor installations at events and retail locations.

Frequently Asked Questions