How to Cut a Desk Mat to a Custom Size (Clean Edges, Rounded Corners)

Desk mats come in a handful of standard sizes and desks don’t. A mat that is an inch too wide for the desk, that needs a notch for a monitor arm, or that has to fit a corner desk is a common problem, and the fix is a sharp blade and ten minutes. We hand-cut custom sizes in our shop every day; here is how we do it, scaled down to a kitchen table.

Tools

• A fresh, sharp utility knife or rotary cutter (a 45 mm rotary cutter is the best tool for this).
• A long metal straightedge or a steel ruler at least as long as the cut. A cheap aluminum yardstick from the hardware store works.
• A self-healing cutting mat or a scrap of cardboard under the desk mat.
• A pencil or chalk, a tape measure, and something round for the corners: a coffee mug, a roll of tape, or a quarter.
• Clamps or heavy books to hold the straightedge.

Step 1: Measure the desk, not the mat

Measure the space you want to cover and subtract half an inch on each side so the mat isn’t pushed against a wall or monitor stand. Write the final size down. Measure twice; you can’t un-cut rubber.

Step 2: Mark the cut on the back

Flip the mat print side down on the cutting surface. Mark the cut line on the rubber with a pencil or chalk using the tape measure at three points along the line, then connect them with the straightedge. Marking the back keeps the print clean and the rubber takes a pencil line well.

Step 3: Cut from the back, multiple passes

Clamp or weight the straightedge on the line. Hold the knife vertical (not angled) and make a light first pass to score the rubber, then two or three more passes with steady, moderate pressure until you’re through. Don’t try to cut through in one heavy pass; the blade will wander and the cloth will tear. Cutting from the back means the blade enters rubber first and exits cloth, which gives a clean edge on the print side.

Step 4: Corners

Square corners: just make the two cuts meet. Rounded corners: trace a mug (about a 1.5″ radius) or a roll of tape at each corner on the back, then cut the curve in short overlapping strokes with the utility knife, or in one smooth arc with the rotary cutter. Rounded corners don’t curl and look finished, which is why our stock mats have them.

Step 5: Clean the edge

Run your finger along the cut. Any cloth fuzz can be trimmed with small scissors. A cut seamless mat has an exposed cloth edge; it won’t fray in normal use, but if you want it sealed, a thin line of clear fabric glue along the cloth edge on the back does it.

Notches and cutouts

For a monitor arm clamp or a cable grommet, mark the rectangle on the back, cut the two long sides first, then the short side, and round the inside corners slightly so they don’t tear. For a circle, trace a can and cut in short strokes.

What not to do

• Don’t use scissors on anything longer than a corner; the edge will be wavy.
• Don’t cut a stitched-edge mat and expect the stitching to survive; you’ll lose the border on that side.
• Don’t cut on your actual desk. Blades go through rubber and into wood.
• Don’t cut hot or cold rubber; room temperature cuts cleanest.

Or let us cut it

If you want a specific size printed with your design, our custom size desk mat builder lets you enter any width up to 36″ and height up to 18″, pick rounded or square corners, see the price, and design it in the editor. We hand-cut it in the shop with a $25 cut fee, about a week lead time. It comes out cleaner than a kitchen table, and it’s printed edge to edge for exactly that size, so nothing is cropped.