September 12, 2026
Standard poster board size is one of those dimensions that most people have an instinct about but cannot precisely state. You know it is bigger than a sheet of paper. You know it fits in a science fair trifold. But what are the exact measurements? And how does the poster board size differ from a printed poster size?
This guide gives you exact dimensions for every type of standard poster board, explains how those dimensions relate to printed poster sizes used in marketing campaigns, and tells you which board sizes work for which applications. Whether you are setting up a school display, a trade show presentation, or an indoor marketing installation, the right board size matters.
Our team at American Guerrilla Marketing works primarily with printed paper posters rather than foam core or cardboard poster board. But we understand the full display network, and many of our clients use poster board for indoor displays that complement their outdoor campaigns. This guide covers both worlds.
The most common standard poster board size in the United States is 22 x 28 inches. This is the size you find at most office supply stores, craft stores, and discount retailers when you pick up a sheet of foam core or cardboard poster board. It is the size that fits standard retail display holders and the frames used in school science fairs and community presentations.
Why 22 x 28? The dimensions derive from efficient paper cutting. A standard 22 x 28 inch sheet can be cut from a 28 x 44 parent sheet with minimal waste. Two 22 x 28 sheets come from one parent sheet. The size also fits standard retail display hardware that the office products industry has standardized around.
The 22 x 28 format is noticeably different from the 24 x 36 printed poster standard. If you are trying to display a 24 x 36 printed poster on a 22 x 28 board, it will not fit without trimming. Know the difference before you design for one or order the other.
Standard Poster Board Size: 22 x 28 inches is the most common retail poster board size in the US. Do not confuse this with the 24 x 36 standard printed poster size. They are different products with different dimensions.
A common foam core size available at art supply stores and professional display vendors. The 20 x 30 format is popular for trade show displays, presentation boards, and art presentations. It holds a printed poster up to that size easily. For professional presentation environments, this is a common size choice.
The retail standard. This is what you find packaged and sold at Walmart, Target, Office Depot, Staples, and most craft stores. It comes in both foam core and corrugated cardboard versions. Standard retail display hardware is designed for this size. Science fairs, school presentations, and small business promotions all use this as the default.
Poster board also comes in 24 x 36 to match the standard printed poster size. Foam core at 24 x 36 is available at art supply stores and specialty display vendors. This size is ideal when you want to mount a standard printed poster on a rigid backing for tabletop or easel display without cutting or trimming.
Large format poster board for trade show and event display applications. At three by four feet, this size commands floor space and is typically mounted on an easel or standing frame. Professional display vendors carry this size. It is less common in retail channels but available through specialty suppliers.
Full sheet foam core and gatorboard products come in 4 x 8 foot sizes for large display installations. This is the substrate used for large format display boards at trade shows, exhibition spaces, and large event signage systems. At this size, the product is a substrate for printed graphics, not a standalone display board.
| Product Type | Size (Inches) | Size (cm) | Where to Buy | Primary Use |
|---|---|---|---|---|
| Cardboard Poster Board | 22 x 28 | 55.9 x 71.1 | Mass retail, craft stores | Schools, community, small retail |
| Foam Core (Standard) | 20 x 30 | 50.8 x 76.2 | Art supply stores | Presentations, displays, mounting |
| Foam Core (Retail) | 22 x 28 | 55.9 x 71.1 | Office supply, craft stores | School projects, point-of-sale display |
| Foam Core (Poster Size) | 24 x 36 | 61 x 91.4 | Art supply, display vendors | Mounting standard printed posters |
| Gatorboard (Large) | 36 x 48 | 91.4 x 121.9 | Display and sign vendors | Trade shows, events, retail installations |
| Foam Core / Gatorboard (Full Sheet) | 48 x 96 | 121.9 x 243.8 | Professional display suppliers | Large exhibits, trade show walls |
These two things sound similar but serve different purposes and come in different sizes. Understanding the distinction prevents expensive ordering mistakes.
A poster board is a physical substrate: a rigid or semi-rigid sheet of foam core, cardboard, or plastic foam that you write on, glue things to, or mount printed graphics onto. It is a display surface.
A printed poster is a sheet of paper with ink on it. It may be hung directly on a wall with paste, tape, or pins. It may also be mounted onto a poster board for display on an easel or tabletop stand.
The standard sizes differ. Printed posters most commonly come in 11 x 17, 18 x 24, and 24 x 36 inches. Retail poster board most commonly comes in 22 x 28 inches. If you want a printed poster mounted on a rigid backing, you need to match the two sizes carefully or trim one to fit the other.
Our teams use rigid substrates for specific indoor campaign applications where paper posters would not perform well. Here are the contexts where poster board dimensions matter in a marketing context:
Trade show and event booth displays: A 20 x 30 or 24 x 36 foam core panel mounted on a small easel creates a polished tabletop or floor display that looks professional without requiring permanent installation hardware. The rigid substrate holds its shape under lighting and air conditioning conditions that would cause paper posters to curl.
Retail point-of-purchase displays: Many retail display systems use rigid inserts sized for 22 x 28 or 24 x 36 poster board. Knowing the hardware dimensions lets you spec the right board size without measuring every time.
Event directional signage: Foam core signs at 22 x 28 or 20 x 30 placed on easels at venue entrances and corridors create professional wayfinding systems without requiring permanent installation. The rigid format holds up through an all-day or weekend event better than paper.
Interior window displays: Mounting a printed poster on foam core backing and standing it in a window display creates a more finished presentation than a paper poster taped to glass. The board size should match or slightly exceed the printed poster size for clean edges.
Mounting Tip: When mounting a 24 x 36 printed poster on foam core, use a 24 x 36 board for a flush edge, or a 26 x 38 board for a 1-inch border on all sides. The border gives the display a gallery-mounted look that elevates the visual presentation.
Poster board thickness is not standardized the way dimensions are. Different products and vendors offer varying thickness options that affect how the board is used.
Standard cardboard poster board from retail stores is typically 1.5 to 2 mm thick. It is flexible enough to bend for trifold presentations but not rigid enough for large unsupported display panels. It will sag and bow over time.
Standard foam core is typically 3/16 inch (4.76 mm) thick. This is the most common thickness for art supply and office display applications. It is rigid enough for unsupported panels up to about 24 x 36 without bowing. For larger panels, 1/2 inch foam core is the better choice.
Gatorboard is a higher-density foam core with a water-resistant surface. It comes in 3/16 and 1/2 inch thicknesses and holds up better in humid environments than standard foam core. We recommend gatorboard for any display application near air conditioning vents, outdoor-adjacent windows, or environments with variable humidity.
A quick guide to matching poster board size to application type:
Science fair or school project: 22 x 28 inches. This is the standard size for school display contexts. Most school guidelines specify this size or a trifold variant of it. Available at any office supply or craft store.
Real estate or retail counter display: 22 x 28 or 24 x 36 depending on the available display hardware. Confirm the frame or stand dimensions before ordering the board.
Trade show presentation panel: 24 x 36 for easel displays. 36 x 48 or larger for booth wall panels. Match the board size to the printed graphic size. Buy the board first, then size the print to match.
Indoor event signage: 20 x 30 or 24 x 36 for general use. Use 36 x 48 for high-visibility locations like event entrances and main staging areas.
Street marketing campaign (indoor component): Match the board size to the standard printed poster sizes we use in outdoor campaigns. A 24 x 36 foam core panel with a mounted printed poster creates a consistent indoor/outdoor visual brand experience for events that span both environments.
Poster board has specific uses in marketing and event contexts that differ from printed paper poster campaigns. Here is where poster board size decisions come up in practice.
Trade show displays use foam core and gatorboard poster board in standard sizes from 24×36 up to 36×48 inches. These rigid boards can be mounted on easels, hung from booth structures, or placed in custom-built display systems. The 24×36 foam core format fits most standard easel mounts. The 36×48 requires a larger easel or wall mounting. For trade show displays that travel to multiple events, the lighter foam core is preferable to heavier materials because it reduces shipping weight and costs.
Retail POP displays often use foam core poster board in the 18×24 or 22×28 inch format mounted in floor stands or counter-top display holders. The foam core provides the rigidity required for freestanding displays without requiring the expense of custom printing on rigid substrate. For temporary promotional displays at retail, a high-quality paper print mounted on foam core delivers a professional look at significantly lower cost than printing directly on rigid material.
Events use poster board signage for everything from registration directions to speaker bios to sponsor recognition. Standard 22×28 retail poster board is the most commonly used format for hand-lettered or locally printed event signage. For professionally produced event signage that needs to look polished, 24×36 foam core with a high-quality print laminated to the surface creates a durable, professional-grade sign at reasonable cost.
Political campaigns, advocacy organizations, and grassroots marketing efforts use poster board for handmade signs and hand-delivered messaging. The 22×28 retail standard is the most common format because it is the size most widely available from retail stores. The mobility advantage of poster board over printed paper posters matters in contexts where volunteers are carrying signage rather than installing it on surfaces.
The 22×28 retail poster board format originated as a school science fair and classroom standard. This is still the dominant application for this specific format. For marketing campaigns near colleges and universities, understanding that the 22×28 is primarily a school format rather than a professional marketing standard helps clarify why most professional campaign work uses the 24×36 format even when poster board is the substrate.
The most common standard poster board size in the United States is 22 x 28 inches. This is the size sold at mass retailers, office supply stores, and craft stores. Foam core poster board is also commonly available at 20 x 30 and 24 x 36 inches in art supply and professional display channels.
No. The most common retail poster board is 22 x 28 inches. The most common printed poster is 24 x 36 inches. They are different sizes. A 24 x 36 printed poster will not fit flat on a 22 x 28 board without trimming. If you plan to mount a printed poster on a board, order poster board at 24 x 36 specifically to match.
The 22 x 28 size is available at Walmart, Target, Office Depot, Staples, Michaels, and most grocery stores. The 20 x 30 and 24 x 36 foam core sizes are available at art supply stores like Blick and Utrecht, and from professional display vendors. Large format boards (36 x 48 and up) are typically available only from specialty display and sign supply companies.
The conventional science fair poster board is either 22 x 28 inches (flat) or a trifold board that opens to approximately 36 x 48 inches (with 12-inch side panels). The trifold is the most recognizable format for science fair presentations. Most school guidelines specify one of these two formats.
Foam core is a rigid substrate made of a polystyrene foam core sandwiched between two layers of paper. It is lightweight, holds its shape well, and cuts cleanly for custom sizes. Cardboard poster board is thinner, more flexible, and less expensive. Cardboard is fine for temporary applications and trifold presentations. Foam core is better for display applications where rigidity matters.
Standard foam core and cardboard poster board are not designed for outdoor use. Moisture causes warping and delamination quickly. For outdoor display applications, use printed paper posters with appropriate outdoor adhesive for wall mounting, or use UV-resistant vinyl-printed rigid substrates designed for outdoor use.
Standard cardboard poster board (the retail kind) is typically 1.5 to 2 millimeters thick. Standard foam core is 3/16 inch (approximately 5 mm) thick. Heavy-duty foam core is 1/2 inch thick. Gatorboard, a denser version of foam core, is typically available in 3/16 and 1/2 inch thicknesses and is more resistant to denting and moisture than standard foam core.
In retail channels, the largest commonly available poster board is typically 22 x 28 inches. Through art supply stores, 24 x 36 and 30 x 40 inch foam core sheets are available. Professional display vendors stock foam core and gatorboard up to 48 x 96 inches (4 x 8 feet), which is the standard substrate size for trade show and exhibition display systems.
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