Sudoku Difficulty Levels Explained: Easy to Expert
Have you ever played a "Hard" sudoku that felt the same as "Medium"? That happens when difficulty is set only by how many numbers are given. The number of clues matters a little, but what really makes a puzzle hard is the technique you need to find the next move.
Easy
Around 40 clues. Every move can be found with hidden singles: pick a number, scan a box, find the only spot. Great for warming up or learning.
Medium
Fewer clues, around 32. You will sometimes need a naked single: a cell where every other number is already taken.
Hard
Around 29 clues, and at least one step needs locked candidates: a number confined to one row or column inside a box lets you cross it out elsewhere.
Expert and Master
26 or fewer clues and naked pairs: two cells that share the same two candidates remove those numbers from the rest of the unit. Master has the fewest clues.
How to move up a level
- Finish three or four puzzles in a row without hints before moving up.
- When you use a hint, read the technique name and try to spot the same pattern yourself next time.
- Use pencil notes from Hard upwards; the patterns are almost invisible without them.
Inkdoku grades every puzzle this way: its generator checks which techniques the solve needs, so each level feels different, and no level ever requires guessing.
FAQ
Why does Hard sometimes feel like Medium in other apps?
Many apps grade puzzles only by the number of clues. Two puzzles with the same clue count can need very different techniques.
How many clues does a sudoku need?
At least 17 for a unique solution. Most puzzles for people have between 24 and 40.
Which level should I start with?
Start with Easy to learn scanning, then move up once you can finish without hints.