How To Cut Foam Board for a Clean Finish

by Sean McCafferty on January 20, 2023
How to Cut Foam Board

Anyone who has ever tried cutting foam board understands the difficulty involved. Knowing how to cut foam board to get clean, professional-looking edges requires a little know-how, but it's a skill you can master with practice.

Whether you use foam board for art projects, marketing presentations or architectural renderings, it's essential to know how to cut foam poster board (aka foam core). We'll supply the tips and tricks you need to get clean edges every time.

Make sure you have the correct cutting tool, a straight edge, a supply of foam board and a good cutting surface to get started.

The Right Tool for Cutting Foam Board

Your best bet for cutting foam board is using an X-ACTO knife or utility knife with a NEW blade. Used properly, you'll slice through your foam board like a pro, and the finished product will be impressive.

Just to cover all the bases, let's talk about what NOT to use when cutting foam board. While some have tried to hack through layers of foam board using scissors, knives or saws, we don't recommend them – unless you're okay with jagged edges. As for hot knives or hot wires, you (and your foam board) risk getting burned or blistered using these methods.

The Best Way to Cut Foam Board

Many people use a trial-and-error method, but you can save yourself much time and aggravation if you skip right to the best way to cut foam board. Here are the steps to follow:

  1. Measure: As with anything you cut, it's essential that you measure twice and cut once. Unlike other materials, you won't be able to glue foam board back together if you make a mistake.
  2. Align: Line up your ruler, T-square or other straightedge tool along the line you want to cut. Hold it there firmly.
  3. Poke: Stick the tip of your X-ACTO knife into the top paper layer where your line begins.
  4. Angle: Shift the angle of your knife so it's no more than 30 degrees from your foam board's surface. The angle of your knife is crucial because a bad angle gives you tears and snags.
  5. Slice: Cut alongside your straightedge. Don't worry about slicing all the way through the foam board.
  6. Re-Slice: You'll need to make about three passes through the foam board to cut it cleanly.
  7. Trim: If necessary, use your knife or a pair of scissors to trim away any stray bits of foam board.

How to Cut Foam Board Circles

There are two tools you can use to help you cut foam board circles. While you can try cutting a circle without using one of these tools, you won't get the nice rounded edge you're looking for.

Try a Compass

A fill source reflects the primary light back onto the subject to fill in any shadows that are detracting from the shot. In this case, white foam board acts as the fill light source. This technique is used in both portrait photography and product shots.

  1. Mark the center of your hole with a pencil.
  2. Use the compass to make a circle on the face of the foam board.
  3. Stick a pin through the hole you've marked and turn the board over.
  4. Once again, draw a circle with the compass using the hole as the center point.
  5. With your utility knife or X-ACTO knife, trace around the pencil line and penetrate the top layer.
  6. Turn the foam board over and repeat, cutting the foam board's top layer on that side.
  7. Follow up with the knife to slice through the remaining layers of foam.

Use a Circle-Cutting Tool

The easiest method for cutting foam board circles and curves involves using special foam board tools designed for the task. A foam board circle cutter operates much like a compass. The only difference is the circle-cutter holds a blade instead of a pencil:

  1. Mark your circle on both sides of the foam board using the same method as the compass.
  2. Set the tool so the center spot is its pivot point, with the outer blade hitting the circle you marked.
  3. Secure the pivot point as you rotate the blade around the circle.
  4. Depending on your board's thickness, you may need to cut both sides, as indicated in the compass method.

Learning How to Cut Foam Board Is Easy With Quality Materials From

Once you know how to cut foam board, ensure you have the best materials to give your project the clean, professional look it deserves. has craft foam board and gator board in various weights and thicknesses. Find yours at today!

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