ROT5 adds 5 to each decimal digit modulo 10: 0↔5, 1↔6, 2↔7, 3↔8 and 4↔9. Any character that is not a digit is left completely unchanged.

Why is ROT5 its own inverse?

Because five is exactly half of ten, rotating a digit forward by five and then by five again lands you back where you started. So the same operation both encodes and decodes — there is no separate decode mode.

How is this different from ROT13?

ROT13 rotates the 26 letters by 13 and ignores digits. ROT5 rotates the 10 digits by 5 and ignores letters. They are complementary, and combining both gives ROT18.

Does ROT5 change letters or symbols?

No. Only the characters 0 through 9 are affected. Spaces, punctuation, and every letter pass through exactly as typed.

Not at all. With no key and only ten possible digit values, it offers no real protection. Use it for puzzles, light obfuscation, or as a teaching example, never for sensitive data.

What is the ROT5 Digit Rotator?

Free ROT5 digit rotator — shifts the ten decimal digits by five (0↔5, 1↔6, 2↔7, 3↔8, 4↔9) while leaving letters and symbols untouched. The perfect numeric companion to ROT13, all in your browser. It runs free in your browser on Gera Tools, with nothing uploaded.

ROT5 Digit Rotator — Gera Tools

Name: ROT5 Digit Rotator
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

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ROT5 is a tiny substitution cipher for numbers. It rotates each decimal digit by five places, so 0 swaps with 5, 1 with 6, and so on. It is the numeric sibling of the well-known ROT13 letter cipher and is most useful for puzzles, obfuscating order numbers in screenshots, or teaching modular arithmetic. This tool applies ROT5 instantly and leaves all non-digit characters untouched.

How it works

For every character, the tool checks whether it is a digit from 0 to 9. If it is, the new value is (digit + 5) mod 10. That gives the pairs 0↔5, 1↔6, 2↔7, 3↔8 and 4↔9. Any character that is not a digit — a letter, space, or punctuation mark — is copied straight to the output with no change.

Because the rotation amount (5) is exactly half the number of digits (10), ROT5 is a self-inverse operation. Running it twice returns the original text, which is why a single button both encodes and decodes.

The complete digit mapping

Original	Rotated
0	5
1	6
2	7
3	8
4	9
5	0
6	1
7	2
8	3
9	4

Every digit pairs with the digit exactly five steps away, and every pair is symmetric.

Worked example

The string Order 1234 ships in 7 days becomes Order 6789 ships in 2 days: the digits 1, 2, 3, 4 rotate to 6, 7, 8, 9 and the lone 7 rotates to 2, while every letter and space is preserved.

Running Order 6789 ships in 2 days through ROT5 again gives back the original — the self-inverse property in action.

Practical uses

Obfuscating order or invoice numbers in screenshots — the digits look random but the letters around them stay readable, so the context is clear without revealing the actual ID
Puzzle hunts — ROT5 is a common encoding in cryptographic puzzles that mix text and numeric clues
Teaching modular arithmetic — the (digit + 5) mod 10 formula is one of the simplest real examples of modular arithmetic students encounter
Combined with ROT13 — combining ROT5 (digits) and ROT13 (letters) gives ROT18, which scrambles the entire alphanumeric range in one step

ROT5 has no key and a trivially small key space, so it is not encryption — treat it as a puzzle or obfuscation toy. Everything runs locally in your browser; your text is never uploaded.