Cryptogram Generator

Type a quote, a fun fact or a class message and turn it into a secret-code puzzle. Choose a random letter swap or a Caesar shift, give away a few letters, and print it with the key.

51/400 characters
Code type

Crack the Code

Name ____________________ Date ________

Each letter stands for a different letter. Crack the code to read the message. Some letters are filled in to get you started.

TTHEEBEESTTWAYTTOPRREEDICTTTTHEEFUTTURREEISTTOCRREEATTEEITT.
CodeABCDEFGHIJKLMNOPQRSTUVWXYZ
Real

Crack the Code: answer

THE BEST WAY TO PREDICT THE FUTURE IS TO CREATE IT.

Code: THE BEST WAY TO PREDICT THE FUTURE IS TO CREATE IT.

How to solve a cryptogram

  1. Start with one-letter words. In English they are almost always A or I.
  2. Look for THE. A three-letter code word that appears more than once is very likely THE, which also gives you T, H and E everywhere else.
  3. Use apostrophes. A single letter after an apostrophe is usually S or T ('S, N'T).
  4. Count letters. The most frequent code letter in a longer message is probably E. The explainer beside this shows how that works.

Ideas for the classroom

  • Encode the answer to a riddle, or tomorrow's homework instructions.
  • History: encode a famous quote and let students guess the speaker from the hint.
  • Maths: Caesar shifts are modular arithmetic in disguise. Shift 25 is the same as shifting back 1.

Frequency analysis: how code-breakers crack substitution ciphers

A letter swap hides letters but not how often they appear. Compare the most common code letters with the most common letters in English and you already have good guesses. The Arab scholar al-Kindi described this method in the 9th century.

Coded message, top 10

O20.7%
X13.3%
M8.1%
T8.1%
G7.4%
J5.9%
C5.9%
I5.2%
K3.7%
E3.7%

Typical English, top 10

E12.7%
T9.1%
A8.2%
O7.5%
I7%
N6.7%
S6.3%
H6.1%
R6%
D4.3%

Coded: ODOJB XKGO C IOXXOJ JOUOCXM KE XLO GOMMCYO KX POWTGOM XLO MCGO WTRO IOXXOJ, MT XLO GTMX WTGGTE WTRO IOXXOJM CJO UJTPCPIB…

Questions teachers ask

What is a cryptogram?

A short text in which every letter has been swapped for a different one, always the same way: if E becomes Q once, every E is a Q. Solvers use letter patterns and common words to crack the code.

How do I make a cryptogram easier for kids?

Give away a few letters (the "Reveal letters" setting), use a Caesar shift so the whole alphabet moves by the same amount, or print the key grid with some letters filled in. Short, familiar sentences are easiest.

What is a Caesar cipher?

The code Julius Caesar reportedly used, described by the Roman historian Suetonius: every letter is shifted the same number of places along the alphabet. With a shift of 3, A becomes D and B becomes E. Once students find one letter, they have the whole key.

Can a letter stand for itself?

Not in the random cipher here: the generator makes sure no letter maps to itself, which is the usual rule for published cryptograms.

More puzzle makers