Science fair board size: the standard tri-fold in inches and centimetres

The standard science fair board is a tri-fold that is 36 inches tall and 48 inches wide when it's open: a 24-inch middle panel with a 12-inch wing on each side. That's about 91 × 122 cm. It stands up on a table by itself, it fits inside the size limits of the fair rules I read, and it's the size the board tools on Peabody are drawn for. Smaller boards are sold too, but buy the 36 × 48 unless your school's sheet asks for something else.

I built Peabody's board layout tool to that size, so every card it plans is in real inches. Here are the numbers behind it. I checked each one on the store's or the fair's own page on 31 October 2026.

The standard board, panel by panel

Brands round the panels a little differently, so measure yours before you cut cards to fit:

• Hobby Lobby's Flipside foam board lists its panel widths as 12 and 24 inches, 36 × 48 overall and a quarter of an inch thick (Hobby Lobby's product page, read 31 October 2026).
• Hobby Lobby's cardboard project display board is also 36 × 48, but lists its panel widths as 12.75 and 22.5 inches. The middle is an inch and a half narrower than the foam one.
• Target's up&up corrugated board is listed at 36 × 48 inches and 0.24 inches thick (Target's product page, read 31 October 2026). A shopper's answer on Target's foam board page says it is 48 inches wide and 36 tall when fully open, which is the right way round: the 48 is the width.

Folded, the wings close over the middle panel, so a closed board is roughly the size of the middle: about 2 feet wide and 3 feet tall. That's worth knowing for the car ride to school.

Smaller boards

Not every tri-fold on the shelf is the standard one. Target also lists a white tri-fold at 28 × 40 inches (read 31 October 2026), and desk-sized mini boards are smaller again. A small board is fine for a classroom share. For a fair it's tight: a board has to carry a title, six sections and a graph big enough to read from a step back. On a 28 × 40 board the results card shrinks to roughly two sheets of printer paper side by side.

If your school sends home a size, use it. If it only says "a tri-fold", it means 36 × 48.

What the fair rules allow

Elementary fairs write their own rules, and most just say "a standard tri-fold". The big fairs set a limit. Society for Science's ISEF Display and Safety Rules (read 31 October 2026) allow a project up to:

• 76 cm deep, front to back (about 30 inches);
• 122 cm wide, side to side (about 48 inches);
• 240 cm high, measured from the floor (about 94 inches).

The same page says a table you use becomes part of the project and has to fit the limits, and that the tables ISEF provides are no more than 91 cm (36 inches) high. So the standard board is right at the width limit, and on a 36-inch table its top is at 72 inches, well under 240 cm. With its wings angled in, a tri-fold is only about a foot deep.

Size is the easy rule. The ones that catch families out are about what sits on the table: ISEF's page bans all liquids, water included, at the display. Peabody's rules page lists the bans the rule sets share. Your school's sheet wins.

How the space is shared out

On a 36 × 48 board, Peabody's classic layout leaves a one-inch edge and gives each part this much room:

The results get the biggest card because the table and the graph are what a judge points at. The display board layout post goes through each section and what to write in it.

Try tonight

The drawing at the top of this page is the classic layout to scale, every section labelled with its size. Measure the middle panel of the board you have, or the one you're about to buy. Then open the board layout tool, pick a layout and print the plan at 1:12, where an inch on paper is a foot on the board. When the plan looks right, the board kit prints every card at its real size on ordinary Letter or A4 paper, with a 10 cm bar on each page so you can check the printer didn't shrink it.

Questions grown-ups ask

Is 36 × 48 the same as 3 by 4 feet?

Yes. 36 inches is 3 feet and 48 inches is 4 feet. Some shops write it 48 × 36; it's the same board.

Foam or cardboard?

Either does the job. Foam is lighter and stiffer and costs more; cardboard is cheaper and takes glue well. What each costs, and a free way to make one, is in what a science fair board costs.

Can the board be bigger than 36 × 48?

Only if your fair says so. A bigger board won't fit the table space most schools give each project, and at the largest fairs 122 cm is the widest a project may be.

Peabody (peabody.kids) is free through the end of 2026, with no ads and no sign-up. The library has a story for the evening the glue is drying.