DollarWise

Free Caesar Cipher Encoder & Decoder

October 12, 2026 · 2 min read · By the DollarWise team

How it works

A Caesar cipher shifts every letter of your message by a fixed number of places in the alphabet. Pick a shift, choose a direction, and see the result live. Not sure which shift a coded message used? The brute-force table at the bottom shows all 25 possible shifts at once so you can spot the readable one.

Caesar Cipher Encoder & Decoder

Shift letters by any amount — includes ROT13 and a brute-force table of all 25 shifts.

100% Free Forever No Sign-up No Credit Card Private — files never leave your browser Unlimited Use

1 Enter your message

2 Shift & direction

Encoding and decoding are the same operation — just pick the opposite direction (or the complementary shift).

3 Result & brute-force table

🔐 Shifted text

🔍 All 25 shifts — spot the readable one

Type a message above and every possible shift will appear here.

Rows show your text shifted forward by each amount. If a message was encoded with shift 3, the readable row is +23.
🎉 Free forever. No sign-up. No credit card. No limits.

This tool runs entirely in your browser — encode and decode as many messages as you like.

Everyday uses

  • Puzzles and geocaching: decode the shifted clues hidden in puzzle hunts and cache listings.
  • Hiding spoilers: ROT13 is the classic way to post spoilers that readers reveal only if they choose.
  • Classroom codes: teach basic cryptography and let students pass “secret” notes.
  • CTF and coding practice: brute-force a shift cipher instantly instead of trying keys by hand.

Frequently asked questions

What is ROT13? ROT13 is a Caesar cipher with a shift of 13. Because 13 is half of 26, applying ROT13 twice returns the original text — the same operation both encodes and decodes.

Is a Caesar cipher secure? No — with only 25 possible shifts it can be broken at a glance (that’s exactly what the brute-force table does). Use it for fun, puzzles, and learning, never for real secrets.

What happens to numbers, spaces, and punctuation? They pass through unchanged. Only A–Z and a–z letters are shifted, and capital letters stay capital.