Cardboard Knight Costume




Introduction: Cardboard Knight Costume

Last Halloween I had difficulty coming up with a costume idea. As a full time college student, I didn't have much time to come up with ideas and I was forced to develop a costume on Halloween day. After searching online for an hour, I saw a cardboard knight helmet. The helmet was cheap and easy to construct and I had most of the materials in my room. The only material I had to collect was cardboard, which was readily available in my dorm's recycling center. After constructing the helmet, I decided to make a sword, shield, and body armor. About 2 hours later, I had completely constructed this costume and was headed to a Halloween party.

Time Needed:

Approx. 3 hours

The longest building step was covering the finished armor with tape. This step sometimes doubled the build time.

Materials Needed:

  • Cardboard
  • Box Cutter/Utility Knife and/or Scissors
  • Duct Tape (in a color of your choice, I chose silver)
  • Pen/Marker


Box Cutters, Utility Knives, and Scissors have sharp blades. Please be careful and safe when constructing this costume.

Tips for Safe Cutting:

Step Breakdown:

  1. Helmet
  2. Shield
  3. Weapon
  4. Chestpiece (Breastplate and Backplate)

How to score cardboard:

Scoring cardboard is a method used to bend cardboard. Box cutters, utility knives, and X-ACTO knives are the easiest tools for scoring, but scissor blade can be used if you don't have these tools. To score cardboard, make a straight cut less than the thickness of the cardboard.

Note: Cardboard has three layers: two paper and a corrugated liner.The two methods of scoring cardboard are as follows:

  1. Cut through the top layer of paper leaving both the corrugated liner and bottom paper layer uncut
  2. Cut through the top layer of paper AND the corrugated line leaving the bottom paper layer uncut

Below is a video about scoring cardboard:

A note on personalization

I am using silver duct tape as a building material and as a decorating material. If you think another color looks better, use it.

Other additional decorations that could make your costume stand out include, but are not limited to:

  • Insignias
  • A cape
  • Feathers
  • Paint

Also,please change the size of the components as you see fit.

Now to the build!!!

Step 1: Sword

My sword is classified as a short-sword. I decided to keep the sword short so that I could swing it without breaking or bending it.

Build Time:

20 - 30 mins

Sword Parts:

Piece 1 (Sword Shape) = 24" x 5.5" Quantity: 1

Piece 2 (Long support) = 22.5" x 1" Quantity: 2

Piece 3 (Short Support Horizontal) = 5.5" x 1" Quantity: 2

Piece 4 (Short support Vertical) = 7" x 1" Quantity: 2


  1. Draw and cut out all pieces, see the dimensions and quantities above
  2. Assemble the sword sandwich
    1. Piece 1 is the center of the sandwich
    2. Place Piece 2 on top of Piece 1, flush with the bottom of the sword's handle. Tape into place.
    3. Place Piece 3 across Pieces 1 and 2,flush with the hilt edges. Tape into place.
    4. Place Piece 4 last. Its base should be flush with the bottom of the sword's handle. Tape into place.
    5. Repeat 2.2 - 2.5 for the other side of the sword.
  3. Cover the sword with tape. (Optional)

Step 2: Helmet

The fastest helmet I could make was a helm. My helm is a cylinder with eye-holes cut out.

Build Time:

20 - 30 mins


  1. Measure the circumference of your head. (My head is approximately 22" around)
  2. Find a piece of cardboard about 5" longer (or more) than your head's circumference. My piece was approximately 27" x 11". (11" was a perfect height for my head, your's may vary. I recommend also measuring the height of your head before selecting and cutting a piece of cardboard.)
  3. Score the cardboard vertically, bend into a cylinder, and tape it in place.
  4. Cut out eye-holes
    1. Place the helmet on your head and mark the approximate position of your nose
    2. Cut eye-holes of your desired shape, I chose rectangles, using your nose mark as reference
  5. Wrap the helmet in tape. (Optional)


DO NOT cut the eye-holes while wearing the helmet, you may injure your eyes.

Be careful when taping the helmet as the tape adhesive can stick to hair.

Step 3: Shield

When completed, this shield takes on an arrowhead shape, also called heater-shaped.

Build Time:

20 - 30 mins

Shield Parts:

  • Main plate
  • Curved support
  • Crossbar
  • Handle


Main plate:

  1. Cut an arrowhead shape in a large piece of cardboard. My piece of cardboard was approximately 23" long by 20" wide. See Heater Shield picture 1/6.
  2. Score the shield lengthwise. When scoring this shield you can either cut along vertical lines or angled lines, I used angled lines. Vertical lines will make a uniform curve, while angled lines make the shield seem more curved at the base than at the top. See Heater Shield picture 2/6.
  3. Bend/fold the shield along these score lines to form a curved surface. See Heater Shield picture 5/6.

Curved support:

Note: The dimensions of the support will depend on the curve of your shield.

  1. Cut out a small rectangular piece of cardboard, my piece was approximately 13" long x 3" wide
  2. Cut a curve on one side of the cardboard rectangle corresponding to the curve of your shield. See Heater Shield picture 3/6.
  3. Tape the curved support about 1/3 of the length of the shield from the top. See Heater Shield picture 4/6.


Note: The dimensions of the crossbar will depend on the size of your shield.

  1. Cut out another small rectangular piece of cardboard of similar size, my piece was 13" long x 3" wide. See Crossbar picture 1/3.
  2. Score this piece lengthwise as shown in Crossbar picture 1/3.
  3. Fold the piece into a triangular beam and use tape to keep the shape. See Crossbar pictures 2/3 and 3/3.
  4. Place the crossbar on top of the curved support extending toward the base of the shield. One end should be resting on the crossbar while the other rests near the point on the shield. Tape the crossbar in place. See Heater Shield picture 4/6.


  1. Cut a long and thin rectangular piece of cardboard approximately 12" long and 1" wide.
  2. Fold the piece into a D shape and tape the flat side below the curved support to form a handle. See Heater Shield pictures 4/6 and 5/6.

Step 4: Chestpiece (Breastplate and Backplate)

My chestpiece is more of a cardboard vest than armor; however, the silver duct tape improved its look. Wearing a gray shirt would also improve its appearance.

Build Time:

60 - 90 mins

Chestpiece Parts:

Technically, the two pieces are a breastplate and backplate, but I made them identical. I have a very flat chest and stomach, but if you are a female or have a different physique than I do, your breastplate may be shaped differently. If you are in this category, I suggest using the set of instructions below:


  1. Find/cut a piece of cardboard larger than your torso. My torso measures about 28" x 18" if I were 2D.
  2. Cut a head hole, you can use your measurements from the helmet section if you have them.
  3. Cut arm slots, these are curved holes that allow arm movement. See the above pictures.
  4. Score the piece along the lines shown. (Note: Two directions are shown in the third picture. This allows the chestpiece to curve over your shoulders and around your torso.)
  5. Cut excess cardboard from the base of the piece. It should fit over your chest with a small amount of excess on the edges.
  6. Cut a curve at the base of the piece. This increases your flexibility when wearing the chestpiece by allowing you to bend over easier.
  7. Trace the completed piece onto another, similarly sized, piece of cardboard.
  8. Repeat steps 2 - 6.
  9. Bend/fold both pieces along the score lines.
  10. Tape the pieces together, both at the shoulder straps and the waist. Leave a space large enough between the two piece for your torso.
  11. Cover with tape. (Optional)

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    2 Discussions


    3 years ago

    cool! That sword looks great! A bit of paint work and it would look even cooler!


    3 years ago

    That's a fun idea for Halloween :)