OnlinePuzzles.org - Free Online Puzzle Games. OnlinePuzzles.org is a free online puzzle game platform offering Sudoku, Number Puzzle, Word Puzzle, and Memory Match games. Part of FlameAI Studio ecosystem. No registration required. Instant play. Brain training and cognitive development through logic puzzles, spatial reasoning games, word games, and memory games. Educational resources, puzzle strategies, and brain training articles available. Publisher: FlameAI Studio. Location: Global. Language: English (US).

OnlinePuzzles.org

Hard Printable Sudoku

Download printable hard Sudoku puzzles. Each PDF includes a clean grid and a separate answer key.

Today's Hard Sudoku - December 23, 2025 (UTC)

This printable set changes daily.

Today's printable set - December 23, 2025 (UTC). New puzzles rotate daily (UTC).
Today - December 23, 2025 (UTC)
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Today's Hard Sudoku

Puzzle ID: 247 - Updated: December 23, 2025 (UTC)

One puzzle per page. Includes PDF answer key.

Today's printable set - December 23, 2025 (UTC)

Download PDFAnswer Key
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Looking for previous days? View printable archive

Explore other printable Sudoku levels:

EasyMediumHard

Key Points

  • One daily Sudoku puzzle per difficulty keeps the focus clear.
  • UTC rotation ensures the daily set is consistent.
  • PDF downloads match the on-page preview.
  • Answer keys are included for every puzzle.

Steps

  1. Review today's preview and confirm the date label.
  2. Download the PDF and answer key as needed.
  3. Return tomorrow for a fresh printable set.
  4. Play online via Sudoku for instant play.

Examples

Easy is ideal for a short daily warmup before work.

Medium is a balanced option for regular practice.

Hard is a focused challenge for advanced solvers.

FAQ

Does the puzzle change every day?

Yes, the daily set rotates using a UTC date seed.

Can I reprint a past puzzle?

Yes, use the printable archive to select a prior date.

Is the answer key included?

Each puzzle has a separate answer key PDF.

Which difficulty should I choose?

Easy has more givens, Medium balances, and Hard uses fewer clues.

Do I need an account to download?

No account is required for printable downloads.

Where can I play online?

Use Games or Daily for online play.

Summary

Daily printable Sudoku keeps each difficulty focused with a single puzzle and a reliable PDF workflow. Consistent rotation supports a steady practice routine.