What is the rail fence cipher?

The rail fence cipher writes the message in a zigzag down and up across several rows, called rails, then reads each row left to right. The letters stay the same but their order is scrambled. It is a transposition cipher, so letter frequency looks like normal English, which is a good clue that you are dealing with one.

Set the number of rails, or turn on "Try all" to decode with 2 to 10 rails and put the most English-looking result first. Some puzzles remove spaces before encoding, so try the "Remove spaces first" option if the result is close but off.

Example

WECRLTEERDSOEEFEAOCAIVDEN with 3 rails is WEAREDISCOVEREDFLEEATONCE.