Utility knife: what it does and when to reach for it

Learn to hold, cut with, and change blades on a utility knife safely and cleanly.

UK-01Know what the tool isA utility knife (also called a Stanley knife or box cutter) is a handle holding a razor-sharp blade, usually a long strip scored into segments. You slide the blade out with a button or wheel on the handle. It's for cutting things like cardboard, plasterboard, wallpaper, carpet, string, and thin plastic - not wood or metal.

UK-02Hold it the safe wayGrip the handle firmly with your thumb on top, near the blade end, not gripping the blade edge itself. Keep your other hand and fingers well behind the blade at all times - never hold material with your hand in the cutting line. Cut away from your body, never towards it.

UK-03Check the blade is sharp before you startA blunt blade is more dangerous than a sharp one, because you have to push harder and the knife can skid off the material. Most blades have snap-off segments scored into them - if the tip looks dull or torn, snap it off using the tool's snapping slot or pliers, never your bare fingers.

1 pack · Snap-off utility blades (pack of 10)

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UK-04Score and cut in one smooth passLine up a straight edge (a metal ruler or spirit level) along your cut line and hold it down firmly. Draw the blade along it in one steady stroke, using light to medium pressure - don't saw back and forth, and don't try to cut all the way through thick material in one go. For thicker sheets like plasterboard, score once, then snap the sheet along the line, then cut through the paper on the back.

UK-05Know when to put it downA utility knife is not for wood, metal, tiles, or anything thicker than a few millimetres - forcing it through hard material is how blades snap and fingers get cut. Reach for a saw, tile cutter, or scissors instead. If you find yourself pressing hard and the blade is bending, stop.

UK-06Retract and store the blade after every useSlide the blade fully back into the handle the moment you finish cutting, even if you'll use it again in five minutes. An exposed blade left on a bench or in a pocket is one of the most common causes of cuts. Store the knife in a drawer or toolbox, not loose in a bag.

UK-07Check you've done it rightA good cut is a single clean line with no ragged edges or torn fibres, made without needing more than light pressure. If you're pressing hard, sawing back and forth, or the material is tearing rather than slicing, your blade is blunt - swap it. You should never have needed your free hand anywhere near the blade's path.

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