Secret Codes for Kids: 3 Number Cyphers

Creating secret messages is always tons of fun. Check out these secret codes for kids that involve number cyphers!

Simple Number Substitution Cypher

In a substitution cypher, one letter, number, or symbol represents a letter. In our case, one number represents one letter. A=1, B=2, C=3, and so on. You can choose any numbers in your code. Just be sure the person reading your message has the code and knows which number goes with which letter. Print out a copy of the number substitution cypher here.

Can you decode this message? 8-9, 8-15-23 1-18-5 25-15-21 20-15-4-1-25

Cypher Wheel with Numbers

This is similar to the substitution cypher above only the cypher wheel makes it easy to change up the code. Print out a copy of your own cypher wheel here. Poke a hole in the center of each circle and attach with a brad.

When you write your message, make sure you write down a key for your message recipient. Tell them what one letter equals. For example, A=7 or T=12. This allows your recipient to line up the cypher wheel and decode your message.

Aiden had the most fun using this cypher. He liked spinning the wheel around to choose his code.

I decoded Aiden’s message above using the cypher wheel.

Number Grid

For this cypher, you’ll need to write the alphabet in a 5X5 grid. Two letters will need to share a grid space. I chose X and Y. Use a coordinate system to create the code. Label the columns and rows with numbers 1-5. These number coordinates will become the substitute for the letter. Print out a copy of the number grid cypher here.

For example, letter A is 11 (row 1, column 1). Letter B is 12. Letter W is 53.

For this method I recommend writing your message down before you convert it to numbers. This way you are less likely to miss letters.

You can then write the number cypher on another piece of paper for decoding.

I love how writing secret messages is a fun way for kids to practice writing letters and numbers.

More Secret Message Ideas for Kids

Write secret messages with baking soda. Use chemistry to reveal the invisible ink.
Use glue to write secret messages and art.
Glyphs are another way to make secret messages. Draw a valentine heart glyph or a monster glyph to hide a message about you.

Subscribe to the Inspiration Laboratories weekly newsletter. Each issue has exclusive hands-on science explorations for children, a recap of our latest activities, and special resources selected just for you!