Numberblocks Costume
Bring math to life with a colorful, blocky DIY character look.
Based on the popular educational animated series, a Numberblocks costume is a creative, block-shaped outfit representing one of the friendly number characters. It is a massive hit for kids' Halloween costumes, school events, and group themes. The look is defined by a bright, solid-colored square body featuring the distinct face and block count of a specific number.
- Difficulty
- Medium
- Time
- ~90 min
- Budget
- $15–40
Try it on
See yourself as Numberblocks
One clear photo of yourself; we render you in this costume — face untouched, full body, about 20 seconds.
One render, $1. No account needed — if it fails you're not charged. Pricing.
Your photo is sent to Google's Gemini API to make the render and isn't used for training. Renders are AI-generated and labelled.
Want a different costume on this photo, or a whole group in costume? Open the Try-On Studio.
What you need for a Numberblocks costume
Short on time? Buy it ready-made
Spirit Halloween sells the complete Numberblocks costume — one box instead of 5 pieces.
Square cardboard box
A large, clean cardboard box that fits comfortably over the torso with room for arm and head holes.
DIY: Find a recycled appliance or shipping box of appropriate size.
Bright acrylic paint or colored paper
High-coverage paint or large poster board sheets matching your chosen Numberblock's color (e.g., red for One, orange for Two, yellow for Three, green for Four).
DIY: Wrap the box in colored wrapping paper or plastic tablecloths.
Felt sheets or printed face template
Black, white, and colored felt sheets to cut out the character's large eyes, mouth, and signature number badge.
DIY: Draw and color the face details on white cardstock, then glue them on.
Matching solid-color shirt and pants
A long-sleeve shirt and leggings or sweatpants in the same color as the chosen Numberblock to wear underneath the box.
DIY: Use any solid neutral clothing like black or white if matching colors aren't available.
Utility knife and strong glue
A box cutter to safely cut out the arm, head, and leg openings, and hot glue or spray adhesive to secure the face details.
Rather not assemble it? See ready-made Numberblocks costumes at Spirit Halloween ↗
How to put it together
- 1
Select your number. For example, Numberblock One is a red square with one eye, while Numberblock Four is a green square made of four smaller blocks.
- 2
Carefully cut out a large hole in the top of the cardboard box for the head, and two holes on the sides for the arms. Ensure the bottom is completely open for the legs.
- 3
Paint the entire exterior of the box in the character's signature color, or wrap it tightly in colored paper, securing the edges with heavy-duty tape.
- 4
If making a multi-block character like Four, use a black marker or thin tape to draw grid lines on the box to represent the individual blocks.
- 5
Cut the facial features (large eyes, expressive mouth, and the number badge) out of felt sheets according to the character's design.
- 6
Glue the felt facial features onto the front of the box, ensuring they are centered and secure.
- 7
Put on the matching solid-colored base layer clothing, then carefully lower the decorated box over your head.
Makeup & hair
Keep hair simple or tucked away. If desired, use matching wash-out hair color spray or face paint to add a touch of color to any exposed skin.
Numberblocks for couples, groups, kids & more
- couples
- Go as Numberblock One (red) and Numberblock Two (orange) for a perfect matching pair.
- group
- Have a group of friends or siblings dress as Numberblocks One through Five for a colorful, sequential lineup.
- kids
- This is highly recommended for kids; ensure the cardboard box is cut short enough so they can sit and walk safely.
- Plus size
- Use a larger wardrobe box or opt for a comfortable, oversized solid-color t-shirt with the Numberblock face printed or ironed onto the front.
Tips
- Make sure the armholes are cut extra wide so the wearer can easily move their arms and hold a trick-or-treat bag.
- If wearing the costume to school or an active party, make the box shorter (hip-length) so it is easy to sit down.
- Use lightweight cardboard to keep the costume comfortable for long periods of wear.
- Add reflective tape to the back of the box if trick-or-treating at night for safety.
Numberblocks costume FAQ
- How do you make a Numberblocks costume?
- The easiest way is to use a square cardboard box painted in the character's signature color, cut holes for the head and arms, and glue on felt facial features.
- What is the easiest Numberblock costume to make?
- Numberblock One is the easiest. It requires a simple red square box, a single large eye, and a red star-shaped 'One' badge on top.
- How do you make the costume comfortable for kids?
- Ensure the box is lightweight, the arm and neck holes are smooth (cover raw cardboard edges with duct tape), and the bottom of the box ends above the knees for easy walking.
Did you know? Numberblocks was created by Joe Elliot and produced in partnership with the National Centre for Excellence in the Teaching of Mathematics (NCETM) to help children visual basic math concepts.