A1Z26 Cipher (What it is and How to Teach Your Kids)

I love teaching my kids how to do different secret codes and ciphers. I love that I get to feed their imagination and help take their play to the next level. Who doesn’t remember the intrigue of handing your best friend a secret message that no one else can read? 

If you’re looking to introduce your kiddos into the world of ciphers, you can’t go wrong starting with an A1Z26 cipher. It’s super easy to encode and decode, and a great cipher to teach a young child. 

What is an A1Z26 Cipher?

An A1Z26 cipher (also called a Number Code or Letter-to-Number Cipher) is a basic substitution cipher. Each letter of the alphabet is replaced by its numbered position in the alphabet. For example, A=1, B=1, etc.

In a substitution cipher, the order of letters in the original message (or plaintext) remains the same. In the case of an A1Z26 cipher, each letter is substituted by a number into a coded message (or ciphertext).

This is a great code to introduce kids to secret codes and ciphers. Encoding and decoding an A1Z26 message is simple and straightforward. It takes only a little bit of explanation if any. Simply hand your child an encoded message with either a chart or decoder and they should be able to decode the message themselves. 

If you want to try another simpler for younger kids, check out The Scytale Cipher (What It Is and How to Teach Your Kids).

How to Encode and Decode Messages Using an A1Z26 Cipher

The basic premise of an A1Z26 cipher is to take the alphabet and assign it a number corresponding to it’s place in the alphabet. 

To encode—that is, to convert the plaintext message into ciphertext—take the letters of your message from the top row (plaintext) and replace them with the number on the bottom (ciphertext). 

Using the diagram, we can encode the following message:

Don't trust atoms. They make up everything.

First, find the letter D in the top row and replace it with the number 4 in the second row. The second letter O will be replaced with 15, and so on.

Plaintext: Don't trust atoms. They make up everything.

Ciphertext: 4 15 14 20 20 18 21 19 20 1 20 15 13 19 20 8 5 25 13 1 11 5 21 16 5 22 5 18 25 20 8 9 14 7

Dad Tip: Make sure you have enough space between letters. If the ciphertext for A and B are together, it will look like the number 12, which can be confused with L. 

To decode a message, simply work the other way. Take the corresponding numbers of your coded message from the bottom row (ciphertext) and replace them with the letters of the top (plaintext)

If you want to make things look a little fancier than a chart, you can also hand your kid a cipher wheel. Here’s a free downloadable cipher wheel with corresponding numbers. If you want to add some mystery, age the paper with some old coffee or tea (check out how to age paper here).

You can also go fancy and buy a decoder ring (something much fancier than what you would find in a cereal box). Retroworks makes a cool rotating decoder ring. This is especially great for treasure hunts and escape rooms. 

Another great cipher that uses a decoder is the Caesar Cipher. To learn more, check out The Caesar Cipher (What it Is and How to Teach Your Kids).

A1Z26 Cipher Activity Ideas (Plus a Free Worksheet)

What’s great about an A1Z26 cipher is that it takes little to no explanation. Simply hand your kids a coded message and a decoder and watch them go to work. 

When thinking about different activities to do with your kids, there are a lot of options. If you want to go the route of the worksheet, then look no further! I’ve got one for you, and it’s free (for real free. Not the “give me a bunch of your information so I can sell it and you get spammed” kind of free). 

Learn more: 6 Secret Codes and Ciphers to Teach Young Kids

If you’re looking to up the ante a little, hide the family tablet. Have your kids go around the house decoding clues to find out where it’s hidden. Not far enough for you? Change the password to a number that is a coded word of your choosing. Make them earn that tech-time!

Looking to go the extra mile and win major dad points? Time to create a treasure hunt! Maybe something along the lines of my epic Caesar Cipher Treasure Hunt, this time with A1Z26 ciphered messages. It’ll take some time to prepare, but the kids will have a blast!

You might also like these Treasure Hunt activities:

• A Christmas Treasure Hunt (For the Whole Family)
• Ottendorf Treasure Hunt Activity to Do With Your Kids
• Become Penpals with an Alien (Pigpen Cipher Activity)
• Caesar Cipher Treasure Hunt Activity to Do with Your Kids
• Book Cipher Treasure Hunt Activity to Do with Your Kids