Hepaly · Free Tool
Printable kids' sudokus with a guaranteed unique solution.
A simple sudoku puzzle is a great logic game starting around age 5 or 6. Choose the size, difficulty level, and symbols: numbers, colorful drawings, or letters. Every grid is verified by a solver to ensure it has only one solution, complete with a print-ready answer key.
- Free, no account needed
- Calculated on your device
- No user input is ever sent
Your sudoku grids
Adjust the size, level, and symbols. Use the seed to find the exact same set again later.
Grid 1 · 10 given clues
Grid 2 · 10 given clues
Grid 3 · 10 given clues
Each grid has exactly one solution (verified by a solver: passed).
How to use it
- Choose the size: 4×4 (2×2 blocks) for beginners, then 6×6 (2×3 blocks).
- Select the level (number of given clues) and symbols: numbers, pictures, or letters.
- Set the number of grids and save the seed if you want to regenerate the same series.
- Print the puzzles, set the answer sheets aside, or download a grid as an SVG file.
A worked example
Example: 4×4 sudoku, easy level, symbols: 10 out of 16 clues given. Place each of the four symbols exactly once in every row, column, and 2×2 block. The solver verifies that only one solution exists.
For a hard 6×6, 15 out of 36 squares are given; the thick blocks span 2 rows by 3 columns.
Method, underlying assumptions, and limits
Method. The program constructs a full, valid grid using trial and error, then removes squares at random. After each removal, a solver counts the solutions (up to two); the removal is kept only if the solution remains unique. The level sets the target number of clues: 10, 8, or 6 for 4×4; 24, 19, or 15 for 6×6.
Limits. The count of given clues is a simple estimate of difficulty: an 8-clue grid can sometimes be easier than another. In some cases, the solver cannot remove as many clues as targeted without losing uniqueness; the grid then retains a few extra given clues, which is indicated.
Frequently asked questions
At what age can kids start playing sudoku?
A 4×4 puzzle with picture symbols is often suitable starting at age 5 or 6, doing it together at first using movable tokens.
How do you ensure the solution is unique?
A solver counts the possible solutions for each grid. It is displayed only if exactly one solution is found.
Can it be played without numbers?
Yes: choose pictures or letters, which are helpful for younger children who haven't learned numbers yet.
Are my choices saved?
No, everything is calculated right inside the page without storage.