How to Solve Logic Grid Puzzles: 5 Techniques That Always Work
Short answer: mark every impossible pair with ✗ first, place a ✓ when only one cell is left in a row or column, and copy what you know between categories. Comparison clues ("older than") and either-or clues do the rest. You never need to guess.
1. Use the direct clues
Clues like "Anna is the tea drinker" give you a ✓ right away. Clues like "Ben is not the pilot" give you a ✗. Start every puzzle by marking these. In Inferlo, placing a ✓ also fills the rest of that row and column with ✗ (you can turn this off in Settings).
2. Eliminate down to the last cell
Each person matches exactly one item in each category. When four of the five cells in a row are ✗, the fifth must be ✓. Scan rows and columns after every few marks; this is where most ✓ marks come from.
3. Link categories through a shared person
If Anna drinks tea and Anna is the teacher, then the teacher drinks tea. Mark that ✓ in the drinks × jobs block too. The same works for ✗: if Anna is the teacher and Anna does not own the cat, the teacher does not own the cat.
4. Squeeze comparison clues
"The cat owner is older than the painter" means the cat owner cannot be the youngest and the painter cannot be the oldest. It also means they are different people. Each time you learn more about either side, come back to this clue.
5. Use either-or clues twice
"Clara is either the chef or the pilot" puts ✗ on every other job in Clara's row. If later you learn Clara is not the chef, she is the pilot.
A quick worked example
- Clue: Anna is the tea drinker → ✓ Anna/tea, ✗ the rest of that row and column.
- Clue: The teacher is not Anna → ✗ Anna/teacher.
- Clue: The tea drinker is either the teacher or the chef → since the tea drinker is Anna and Anna is not the teacher, Anna is the chef.
How Inferlo helps
Inferlo gives you a fresh logic grid every day plus unlimited puzzles at four levels, all open from the start. Every grid is checked by a solver so it has exactly one answer. Tap a clue to cross it out when you have used it, and use a free hint if you are stuck.
FAQ
Do I ever need to guess in a logic grid puzzle?
No. A well-made logic grid puzzle has exactly one answer that you can reach by logic alone. If you feel you must guess, look for a cross-category link or a comparison clue you haven't fully used.
Should I mark ✗ or ✓ first?
Mark every ✗ you can from the negative clues first. Most ✓ marks then appear by elimination, when only one cell is left in a row.
What is the hardest kind of clue?
Comparison clues such as "older than" and either-or clues, because they rule out cells in more than one place. Revisit them whenever the grid changes.
Related guides
Practice with a fresh grid every day — Inferlo (Google Play)