How to Answer 11+ Codes Questions

A codes question shows you a word and its secret code, then asks you to write another word in the same code — or to turn a code back into a word. There are two flavours. In a letter code, every letter slides along the alphabet by the same secret jump, so CAT might become DBU. In a number code, every letter swaps for its position in the alphabet — A=1, B=2, C=3, all the way to Z=26 — so CAT becomes 3, 1, 20.

Both flavours look mysterious. Neither is. Every code question is really a counting puzzle: work out the jump once, then use it again. The paper even prints the alphabet above the question so you can count along it with your finger — you are not expected to do it in your head.

Here is the method that cracks them all.

The method

1. Line the word and its code up letter by letter, one directly above the other: S over T, U over V, N over O.
2. Count how far each letter jumped along the alphabet. The jump is usually the same every time — +1, −1 and +2 are the favourites.
3. Check the first letter and the last letter first — they crack most codes fastest. If S→T and N→O, you almost certainly have "+1".
4. Apply the same jumps to the new word. If you are given a code and asked for the word, run the jumps backwards instead.
5. For number codes, learn six anchor letters: A=1, E=5, J=10, O=15, T=20, Z=26. To find any other letter, count on from the nearest anchor. R? That's O plus three, so R=18. No more counting all the way from A.

Worked examples

Example 1: a simple letter code

If SUN is coded TVO (each letter moves on one), what is the code for MAP?

A. NBQ B. LZO C. NBP D. NBR

1. Line up SUN over TVO: S→T, U→V, N→O. Every letter moves on one place.
2. Do the same to MAP: M→N, A→B, P→Q.
3. That spells NBQ.

Answer: A. NBQ

Example 2: a number code

Using A=1 … Z=26, what do 8, 5, 12, 12, 15 spell?

A. HELLO B. HEART C. HOTEL D. HAPPY

1. Use the anchors. 5 is an anchor: E. 8 is three past E: H. 15 is an anchor: O.
2. 12 is two past J(10): L — and it appears twice, so the word has a double L.
3. So the letters are H, E, L, L, O. Only one option has a double letter in the middle — and HELLO is it. (HEART fails at the second number: its second letter is E, but its third is A=1, not 12.)

Answer: A. HELLO

Example 3: a code where the jump grows

The code for SHIP uses +1, +2, +3, +4 on the letters in turn (giving TJLT). What is the code for BOAT?

A. CQDX B. CQCX C. DPCX D. CPDX

1. Here the jump is different for each position: first letter +1, second +2, third +3, fourth +4. Check it on SHIP: S+1=T, H+2=J, I+3=L, P+4=T. It works.
2. Now apply the same growing jumps to BOAT: B+1=C, O+2=Q, A+3=D, T+4=X.
3. That spells CQDX. Notice the wrong options each differ by a single letter — check all four positions before you commit.

Answer: A. CQDX

The traps

• Decoding in the wrong direction. If the question gives you a code and asks for the word, the jumps run backwards. A "+1" code means you step each code letter back one to find the word. This is the single biggest cause of wrong answers on codes.
• Counting the starting letter as jump one. From M, one jump lands on N. If you touch M and say "one", you'll land one letter short every time. Count the steps between letters, not the letters themselves.
• Nearly-right options. The wrong answers are built from your likely slips — each one differs from the right code by a single letter. Getting three letters right proves nothing; check every position.
• Two-digit numbers in number codes. 12 means L, the twelfth letter. It does not mean "1 then 2" (A then B). Read each number whole before you convert it.

Try these yourself

If the code for CAT is XZG (each letter is its opposite: A↔Z, B↔Y …), what is the code for DOG?

A. WLT B. WMT C. VLT D. WLU

BIRD is coded 2,9,18,4 (A=1 … Z=26). Decode 19,23,1,14.

A. SWAN B. SWIM C. STAG D. SWAY

If the code for COW is DPX, what word has the code SFE?

A. TEA B. ROD C. RED D. RAT E. FED

Answers

• 1: A — every letter swaps for its mirror partner across the alphabet: D↔W, O↔L, G↔T.
• 2: A — 19=S, 23=W, 1=A, 14=N (T is the 20 anchor, so 19 sits just before it).
• 3: C — COW→DPX is a +1 code, so run it backwards on SFE: S→R, F→E, E→D.

Related

• The complete 11+ question-type guide
• VR: Word Codes — the harder cousin, where you must work out which code belongs to which word
• VR: Letter & Number Sequences — more alphabet counting, this time in patterns

All example questions come from the Brainblox question bank — practise this question type inside 15 arcade games, timed mock exams and focused practice. Brainblox is an independent app: not affiliated with, endorsed by or licensed by any exam board, school or assessment publisher, and it contains no past papers.