How do I trim excess wallpaper (cutting in)?

Trimming wallpaper—also known as cutting in—is one of the final steps, and getting it right makes all the difference between a clean, professional finish and an uneven look. The good news? With the right tools and technique, it’s pretty straightforward. Whether you're using a sharp knife or scissors, taking your time will help you get crisp, straight edges every time.

Tools You’ll Need:

✅ Craft knife (snap-off blade knife) – The go-to tool for precise cuts. Snap the blade regularly to keep it sharp and avoid tearing the wallpaper.
✅ Plastic broad knife (best straight edge) – Helps guide your knife and protects the wallpaper.
✅ Smoothing tool – Presses the wallpaper into corners and edges before trimming.
✅ Sharp scissors – An alternative to a knife, especially for tight spaces or tricky angles.

How to Trim Excess Wallpaper (Cutting In):

1️⃣ Align the pattern and press the wallpaper into the edge – Before trimming, double-check that your pattern lines up correctly at the seams and edges. Then, use a smoothing tool, plastic broad knife, or even your fingers to crease the wallpaper along the ceiling, baseboard, or corners.
2️⃣ Choose your trimming method:

• Craft knife (best for precision): Hold a plastic broad knife against the edge and run your knife along it in one smooth motion.
  • Snap the blade regularly to ensure a sharp edge and prevent tearing.
• Scissors method: Peel back the wallpaper slightly and trim along the crease with sharp scissors. This can be easier for tight corners but is usually less precise than a knife.

3️⃣ Wipe away excess paste – A damp sponge will take care of any residue before it dries.  If left, it can damage the paint and paper.

Pro Tips for Perfect Cutting In:

✔ Always align the pattern before trimming – Trimming too soon can cause mismatched edges.
✔ Snap the blade often – A dull blade will tear the wallpaper instead of cutting it cleanly.
✔ Use a plastic broad knife instead of a metal ruler/straight edge – It won’t scratch or damage the wallpaper.
✔ Go slow – A steady hand gives a better result than rushing.
✔ Double-check before removing excess – If needed, go over the cut again before peeling away the extra paper.

Final Verdict?

Using a craft knife (snap-off blade knife) with a plastic broad knife is the best method for a professional-looking finish when cutting in. Just remember to align your pattern first and snap the blade regularly to keep it razor-sharp. Trimming with scissors after peeling back the paper can work too, especially in tight spaces.