Sudoku difficulty levels range from Beginner to Expert (Extreme), and each level is defined by how many given digits the puzzle starts with and which solving techniques are required to finish it. A Beginner puzzle gives you 36 or more clues and can be solved by simple scanning. An Expert puzzle starts with as few as 22 clues and requires advanced techniques such as X-Wing and XY-Wing. On internetsudoku.net you can choose from five difficulty levels, all free with no sign-up required.

What Are the Five Sudoku Difficulty Levels?

Most online sudoku sites — including internetsudoku.net — use five standard difficulty levels. Here is what each one means:

Level	Name	Given digits	Techniques needed
Level 1	Beginner	36–45	Scanning, row-column-box elimination
Level 2	Easy	32–36	Scanning, naked singles
Level 3	Normal	28–32	Naked singles, hidden singles
Level 4	Hard	24–28	Hidden singles, naked pairs, pointing pairs
Level 5	Extreme (Expert)	22–26	X-Wing, XY-Wing, advanced chains

What Makes Each Difficulty Level Different?

The technical definition of difficulty in sudoku has two components: clue count (how many digits are pre-filled) and required techniques (the minimum solving method needed to reach the unique solution). Reducing clue count increases the number of empty cells, which forces longer logical chains before each cell can be confirmed.

Beginner and Easy

Beginner puzzles (level 1) start with the most given digits — typically 36 or more — so almost every group (row, column, or box) contains several filled cells. Simple scanning reveals the answer for many empty cells at a glance. Easy (level 2) reduces the given count slightly and requires the solver to also spot naked singles — cells where only one digit remains after eliminating everything present in the same row, column, and box.

Normal

Normal (level 3) puzzles exhaust easy scanning early. To make progress you must use hidden singles: a digit that can only go in one cell within a group, even though that cell still has multiple candidates. Hidden singles are harder to see than naked singles because the key cell does not look immediately obvious — you must check each digit across every group systematically.

Hard

Hard (level 4) requires all the techniques above plus pointing pairs and naked pairs. A naked pair occurs when two cells in the same group share exactly the same two candidates — letting you eliminate both those digits from all other cells in the group. A pointing pair occurs when a digit within a box can only go in two or three cells that share a row or column, letting you eliminate that digit from the rest of that row or column. Hard puzzles typically take 15 to 30 minutes for experienced solvers and are where sudoku stops feeling like a pastime and starts feeling like a serious logical challenge.

Extreme (Expert)

Extreme (level 5, also called Expert) is the hardest standard difficulty. It requires X-Wing — a pattern spanning two rows and two columns — and XY-Wing, a three-cell pivot-and-wing technique that eliminates a digit from cells that can see both wings. Neither technique is easy to see at first; both require a complete, accurate candidate grid before they become visible. Expert puzzles cannot be solved by guessing: each requires sustained logical deduction across the full board.

How Hard Is Expert Sudoku?

Expert sudoku is significantly harder than hard sudoku. In a hard puzzle, most moves are reachable through naked or hidden pairs once you have a full candidate grid. In an expert puzzle, those techniques are not enough — you must find multi-cell eliminations like X-Wing and XY-Wing, which require you to hold multiple rows or columns in mind simultaneously.

An experienced sudoku player who can finish hard puzzles comfortably should expect expert puzzles to take two to three times longer per puzzle while learning the new techniques, and to hit genuine dead-ends that require backtracking through their candidate notes. Most players find expert the level at which sudoku reveals itself as a deep puzzle discipline rather than a quick diversion.

If you want to understand why expert puzzles require these advanced patterns, see our complete sudoku strategies guide — it walks through X-Wing and XY-Wing step by step.

Which Difficulty Level Is Right for You?

• You have never played sudoku before → start at Beginner (level 1). Focus on scanning rows, columns, and boxes.
• You can finish Beginner puzzles easily → move to Easy (level 2) and practise spotting naked singles.
• Easy feels too quick → try Normal (level 3) and learn to scan for hidden singles.
• You want a real challenge but do not know advanced techniques → start Hard (level 4) with our beginner guide and the strategies page open for reference.
• Hard feels manageable after a few sessions → step up to Extreme / Expert (level 5) and learn X-Wing.

How to Move Up the Difficulty Ladder

The most effective way to improve is to master each level's core technique before moving up — not to spend time struggling at a level above your current skill ceiling. Here is the sequence:

1. Play Beginner until every puzzle is solved comfortably through scanning alone.
2. Move to Easy and practise naked singles until they feel automatic.
3. Move to Normal and learn to scan each digit across every row, column, and box to find hidden singles.
4. Move to Hard and practise building a complete candidate grid before solving, then look for naked pairs and pointing pairs.
5. Read the X-Wing and XY-Wing sections of the strategies guide, then tackle Extreme.

For a full walkthrough of each technique, see our step-by-step beginners guide. For depth on each solving pattern, see the sudoku strategies guide.

Frequently Asked Questions

What are the sudoku difficulty levels?

Standard sudoku uses five difficulty levels: Beginner, Easy, Normal, Hard, and Extreme (Expert). Each level reduces the number of pre-filled clues and requires more advanced solving techniques. Beginner puzzles give 36 or more clues and need only basic scanning. Expert puzzles give as few as 22 clues and require X-Wing and XY-Wing techniques.

How hard is expert sudoku?

Expert sudoku is the hardest standard difficulty level. It cannot be solved with the techniques used at hard level — you need X-Wing (a two-row, two-column elimination pattern) and XY-Wing (a three-cell pivot technique). Most experienced solvers find expert puzzles take two to three times longer than hard puzzles and require a complete candidate grid before any progress is possible.

What is the difference between hard and extreme sudoku?

Hard sudoku is solvable using naked pairs, hidden singles, and pointing pairs — foundational techniques most intermediate players know. Extreme (expert) sudoku requires X-Wing and XY-Wing, which eliminate candidates across multiple rows and columns simultaneously and are much harder to spot. Try extreme sudoku here.

What difficulty level should a beginner start at?

New players should start at Beginner (level 1). Beginner puzzles provide enough given digits that every puzzle is solvable by scanning rows, columns, and boxes — no advanced techniques required. Once Beginner puzzles feel easy, move to Easy (level 2) and practise naked singles before stepping up further.

How many clues does each sudoku difficulty level have?

Approximate clue counts by level: Beginner 36–45, Easy 32–36, Normal 28–32, Hard 24–28, Expert 22–26. Fewer clues mean more empty cells and longer logical chains. The exact number varies per puzzle — what matters is which techniques are required, not just the clue count.