Example 1
In a certain code, DOG is written as FQI. How is STONE written in that code?
Answer: C) UVQPG
Each letter is moved 2 places forward: STONE → UVQPG.
Coding-Decoding reasoning questions for competitive exams: rules, worked examples and practice
Coding-decoding questions show how one word is coded and ask you to code another word by the same rule.
Key rules and formulas
- Compare each letter with its code: count the shift (+1, −2, …).
- Check for reversal (word written backwards) or position-based shifts.
- Some codes use letter positions (A=1) or reverse positions (A=26).
- Apply the same rule letter by letter; do not mix rules.
Common traps
- Assuming the same shift for every letter when it changes by position.
- Not wrapping from Z back to A.
Where Coding-Decoding is asked
- IBPS Clerk Prelims (Reasoning Ability)
- IBPS PO Prelims (Reasoning Ability)
- RRB Group D (General Intelligence & Reasoning)
- RRB NTPC CBT 1 (General Intelligence & Reasoning)
- SBI Clerk Prelims (Reasoning Ability)
- SBI PO Prelims (Reasoning Ability)
- SSC CGL Tier 1 (General Intelligence & Reasoning)
- SSC CGL Tier 2 (General Intelligence, Reasoning & General Intelligence)
- SSC CHSL Tier 1 (General Intelligence)
Worked examples
Example 2
In a certain code, BOOK is written as ERRN. How is STONE written in that code?
Answer: A) VWRQH
Each letter is moved 3 places forward: STONE → VWRQH.
Example 3
In a certain code, CAT is written as AYR. How is DOG written in that code?
Answer: B) BME
Each letter is moved 2 places backward: DOG → BME.
Frequently asked questions
What is Coding-Decoding in competitive exams?
Coding-decoding questions show how one word is coded and ask you to code another word by the same rule.
Which exams ask Coding-Decoding questions?
On MockBazaar, Coding-Decoding questions appear in IBPS Clerk Prelims, IBPS PO Prelims, RRB Group D, RRB NTPC CBT 1, SBI Clerk Prelims, SBI PO Prelims, SSC CGL Tier 1, SSC CGL Tier 2, SSC CHSL Tier 1.
What is the most common mistake in Coding-Decoding?
Assuming the same shift for every letter when it changes by position.