Logic Grid Puzzles: Step-by-Step Method and Clue Types
A logic grid puzzle gives you a set of people or objects, two or more categories of attributes, and a list of clues; you mark every match as yes or no in a grid until each item has exactly one value per category. The fastest method is to process the clues that fix a match first, cross out everything that match rules out, then use the "only one cell left" rule and ordering clues to finish. Below you will find the grid set-up, a fully solved 4×4 puzzle, the clue types you will meet, and six practice puzzles with answers.
What a logic grid puzzle is
Every classic logic grid puzzle has the same structure:
- A set of items, usually people (Ana, Ben, Cara, Dev).
- Two or more categories, each with the same number of values (departments, start times, cities).
- A one-to-one rule: each person has exactly one value in each category, and no two people share a value.
- Clues that, taken together, allow exactly one solution.
Each cell answers one question: is this person matched with this value? Because of the one-to-one rule, a tick lets you cross out the rest of its row and column in that sub-grid. That single rule does most of the work.
In employment tests these puzzles appear as deductive reasoning items, often asking for one fact rather than the whole grid.
Setting up the grid
1. List the categories and values, then 2. put the main items (usually people) down the side and the other categories across the top.
3. Add the sub-grid that links the attribute categories. With three categories you need three sub-grids: people × departments, people × times, and departments × times. Many solvers skip the third one and lose clues such as "The Finance employee starts at 8:00", which link two attributes without naming a person.
4. Leave room for an ordering line. If the puzzle uses times, ranks or seat positions, a small number line next to the grid makes "before", "after" and "next to" clues much easier.
Worked example: a 4×4 puzzle solved step by step
Four colleagues, Ana, Ben, Cara and Dev, each work in a different department (Finance, HR, IT, Sales) and start work at a different time (8:00, 8:30, 9:00, 9:30).
- Ben starts at 8:30.
- The Finance employee starts at 8:00.
- Ana works in neither Finance nor HR.
- Cara starts later than the Sales employee.
- The Sales employee starts exactly half an hour after the IT employee.
Step 1: Direct clues. Clue 1 gives Ben = 8:30. Tick it and cross out Ben's other times and the other people at 8:30. Clue 2 is a direct link between two attributes: tick Finance × 8:00 in the departments × times sub-grid and cross out the rest of that row and column.
Step 2: Negative clues. Clue 3 gives two crosses: Ana × Finance and Ana × HR.
Step 3: Find Finance. Finance starts at 8:00, so Ben (8:30) cannot be Finance. Ana is not Finance (clue 3). Clue 4 says Cara starts later than someone, so Cara cannot be the earliest at 8:00, which means she cannot be Finance either. Only Dev is left: Dev = Finance = 8:00.
Step 4: Narrow the rest. Ana and Cara share 9:00 and 9:30. Ana, Ben and Cara share HR, IT and Sales, and Ana is not HR.
Step 5: Use the ordering clue. IT and Sales are consecutive half-hours (clue 5) and both fall in 8:30–9:30, because 8:00 is Finance. So the pair is either IT 8:30 / Sales 9:00 or IT 9:00 / Sales 9:30. In the second case Sales would start last, and Cara could not start later than Sales (clue 4). So IT = 8:30 = Ben and Sales = 9:00.
Step 6: Finish. Cara starts later than Sales, so Cara is not Sales and is at 9:30. That leaves Ana at 9:00 in Sales, and Cara in HR.
| Person | Department | Start time |
|---|---|---|
| Ana | Sales | 9:00 |
| Ben | IT | 8:30 |
| Cara | HR | 9:30 |
| Dev | Finance | 8:00 |
All five clues hold, and no other arrangement satisfies them. The decisive step was testing two cases for clue 5 and rejecting one; that small case split is how most test puzzles are built to be solved.
Clue types and how to mark them
| Clue type | Example | What to mark |
|---|---|---|
| Direct | "Ben starts at 8:30." | One tick, then cross the rest of the row and column |
| Negative | "Ana is not in HR." | One cross |
| Attribute link | "The Finance employee starts at 8:00." | Tick in the attribute sub-grid; transfer it once you know the person |
| Ordering | "Cara starts later than Sales." | Cara cannot be first; Sales cannot be last |
| Adjacency | "P sits immediately left of T." | Treat P and T as a block on your number line |
| Either/or | "Tess leads Gamma or has the 10k budget, but not both." | Write both cases in the margin and test each |
| Exclusion list | "The four people are Ana, the IT employee, the 9:00 starter and Dev." | All named items are different people: cross every pair |
Typical traps
- Forgetting to transfer. You know Dev is Finance and Finance is 8:00, but you never tick Dev × 8:00. Every time you get a tick, check the other sub-grids.
- Reading "after" as "immediately after". "Cara starts later than Sales" allows any gap. Only "exactly", "immediately" or "directly" fixes the distance.
- Missing the end-point eliminations. "X is later than Y" also tells you X is not first and Y is not last. Those two crosses are often the clue's main value.
- Assuming an either/or clue is inclusive. If the clue says "but not both", the case where both are true is ruled out.
- Guessing. A wrong guess contaminates every later deduction. When stuck, reread a clue you have only partly used.
Time strategy for timed tests
In a test, logic grid items usually ask a single question, such as "Who starts at 9:00?". You rarely need the whole grid.
- Read the question first (10 seconds). Knowing the target tells you which clues matter.
- Sketch only what you need (20–30 seconds). For a 3×3 item, a short list is enough. For 4×4 with three categories, draw the grid.
- Process direct and link clues, then ordering clues (60–90 seconds).
- Stop as soon as the target cell is fixed. Check it against every clue once.
- Cap your time. If a puzzle passes about three minutes, choose the most likely option, flag it and move on. Our article on time management in aptitude tests covers how to set these caps for the whole test.
Practice puzzles
The puzzles get harder as you go. Each has exactly one answer that follows from the clues.
Question 1
Kim, Leo and Max each own one pet: a cat, a dog or a fish. Leo owns the fish. Kim does not own the dog. Who owns the dog?
A) Kim B) Leo C) Max D) Cannot be determined
Answer: C. Leo has the fish, so the dog belongs to Kim or Max. Kim does not own the dog, so it is Max (and Kim owns the cat).
Question 2
Three interns, Faye, Gus and Hana, are each based in a different city (Leeds, Bristol, York) and work in a different team (Audit, Tax, Legal). The intern in Leeds works in Tax. Gus is not in Leeds and not in Audit. Hana is in York. Who works in Audit?
A) Faye B) Gus C) Hana D) Cannot be determined
Answer: C. Hana is in York and Gus is not in Leeds, so Gus is in Bristol and Faye is in Leeds, which makes Faye the Tax intern. Gus is not Audit, so he is Legal, and Hana is Audit.
Question 3
Four runners, W, X, Y and Z, finish a race with no ties. X finishes immediately behind W. Y finishes behind X. Z beats Y. Z does not finish second. W does not win. Who finishes third?
A) W B) X C) Y D) Z
Answer: B. W does not win, and W must be directly ahead of X with Y somewhere behind X, so W is second and X third, with Y fourth. Z wins. The order is Z, W, X, Y.
Question 4
Iris, Jon, Kai and Lena each take a different test (numerical, verbal, abstract, logical) on a different day from Monday to Thursday.
- The numerical test is on Monday.
- Lena takes her test the day after Jon.
- Iris takes neither the logical nor the abstract test.
- The abstract test is earlier in the week than the verbal test.
- Kai takes his test on Thursday.
- Iris does not take her test on Monday.
Which test does Lena take?
A) Numerical B) Verbal C) Abstract D) Logical
Answer: C. Iris is not Monday, so she cannot take the numerical test; with clue 3 she takes verbal. Kai is Thursday, so Jon and Lena take consecutive days among Monday to Wednesday, with Iris on the remaining one. If Iris were Monday that breaks clue 6, so Jon is Monday (numerical), Lena Tuesday and Iris Wednesday. Abstract must come before verbal (Wednesday), so Lena on Tuesday takes abstract and Kai takes logical.
Question 5
Five people, P, Q, R, S and T, sit in a row of five seats numbered 1 to 5 from left to right. P sits immediately to the left of T. S sits in seat 5. R does not sit next to Q. Q sits somewhere to the right of T. Who sits in seat 3?
A) P B) Q C) R D) T
Answer: D. P, T, Q and R fill seats 1–4, with the PT block before Q. If P and T sit in seats 1–2, Q and R take seats 3–4 and sit next to each other, which clue 3 forbids. P and T cannot sit in 3–4 because Q must be to their right. So P is in seat 2, T in seat 3, Q in seat 4 and R in seat 1.
Question 6
Four projects, Alpha, Beta, Gamma and Delta, are each led by a different manager (Ruth, Sam, Tess, Umar) and have budgets of 10k, 20k, 30k and 40k.
- Beta's budget is exactly 20k more than Delta's.
- Sam's project has a larger budget than Alpha.
- Either Tess leads Gamma or Tess's project has the 10k budget, but not both.
- Ruth's project has the 40k budget.
- Alpha's budget is not 10k.
Which project does Sam lead?
A) Alpha B) Beta C) Gamma D) Delta
Answer: B. Clue 1 allows Beta/Delta = 40k/20k or 30k/10k. In the first case Alpha and Gamma share 10k and 30k, so Alpha is 30k (clue 5), and Sam would need more than 30k, but 40k belongs to Ruth. So Beta is 30k and Delta 10k. Alpha cannot be 40k, because Sam needs a bigger budget than Alpha, so Alpha is 20k and Gamma 40k (Ruth). Sam needs more than 20k and cannot have 40k, so Sam has 30k: Beta.
A two-week practice plan
| Days | Focus | Volume |
|---|---|---|
| 1–3 | 3×3 puzzles, full grid, no timer. Learn to mark every consequence of a tick | 3–4 puzzles a day |
| 4–7 | 4×4 puzzles with three categories. Always draw the attribute sub-grid | 2–3 puzzles a day |
| 8–10 | Ordering, adjacency and either/or clues. Practise the two-case split | 3 puzzles a day |
| 11–14 | Timed single-question items, three-minute cap each | 8–10 items a session |
After each session, note where you stalled: usually an untransferred link clue or a skipped end-point elimination. If you want more puzzles of this kind, try our advanced logic puzzles and the mixed sets in logical reasoning practice questions. Full timed tests are available in the free practice tests on the main site.
Frequently Asked Questions
How many dimensions can a logic grid have?
Most aptitude test puzzles use two or three dimensions, for example people, jobs and days. Puzzle books go up to four or five. Each extra dimension adds another sub-grid, so a three-dimension puzzle with four values each needs three 4×4 sub-grids.
What if I have more rows than columns?
Classic puzzles have the same number of values in every category, so each row and column ends with exactly one match. If a puzzle has unequal counts, some values are left unmatched or used twice, and you can no longer assume that the last empty cell must be a match.
Can I use a different notation?
Yes. Ticks and crosses, O and X, or 1 and 0 all work. What matters is that you can tell a confirmed match from an elimination at a glance and that you never leave a deduction unmarked.
Are logic grid puzzles the same as deductive reasoning questions?
They are one type of deductive reasoning question. Every answer follows strictly from the clues, with no guessing or outside knowledge. Some graduate test batteries and puzzle-based assessments use them, and the LSAT used a similar format in its logic games section until August 2024.