🧩 Sudoku

A clean Sudoku you can play here or print. Four difficulties, a new daily puzzle, pencil marks and hints — and a printable PDF (with the solution) for pen and paper.

✓ Free Forever · ✓ No Signup · ✓ No Upload · ✓ Works Offline

🔒 Your game never leaves your browser. Every Sudoku is generated and solved on your device, and the daily board is derived from the date — so there is no account, no upload, and nothing about your solving or times is tracked.

Features

  • Four difficulties — Easy, medium, hard and expert — every puzzle has exactly one solution.
  • Daily puzzle — A new shared puzzle each day — everyone gets the same board to compare times.
  • Pencil marks & hints — Jot candidate notes, check your work, or reveal one square when you are stuck.
  • Printable PDF — Export the puzzle and its solution as a clean A4 PDF for pen and paper.

How It Works

  1. Pick a difficulty — Choose easy to expert, or switch on the daily puzzle.
  2. Play — Tap a cell and type — use notes for candidates, or a hint if you get stuck.
  3. Print it (optional) — Export a printable PDF with the solution on the second page.

Use Cases

  • A quick daily brain workout
  • Print puzzles for kids, a classroom or a coffee break
  • Play offline — it all runs locally
  • Build a PDF pack to solve on paper

Frequently Asked Questions

Does every puzzle have a unique solution?

Yes. Squares are only removed while a single solution remains, so you never have to guess between two valid answers.

Is the daily puzzle the same for everyone?

Yes — the daily board is generated from the date, so you and a friend get the identical puzzle to race on.

Can I print Sudoku to do on paper?

Yes. "Printable PDF" gives you a clean A4 sheet with the puzzle, and the solution on a second page.

Is anything uploaded or saved?

Nothing is uploaded: puzzles are generated and checked in your browser — no account, no upload, no tracking. A few things are kept in this browser only (its local storage): a game in progress so you can pick up where you left off, your daily streak, your best Challenge run and the symbol theme you picked. Clearing this site's data removes them.

Which techniques do I need?

Easy and Medium can always be finished with singles alone — a cell with one possible number, or a number with one possible cell in a row, column or box. Hard and Expert often can too, but some need more: pointing pairs, naked pairs, and now and then an X-wing or a longer chain. Every puzzle still has exactly one solution; if you are stuck, Hint fills one square.

Notes from Milo 🐨

2026-10-25

My how-to guide tells beginners to start on Easy and promises the techniques in it are enough. So I ran 1,600 puzzles through a solver that only knows those techniques: about 1 Easy in 200 and 1 Medium in 20 needed more. From tomorrow's daily on, every Easy and Medium can be finished with singles alone. Hard and Expert still sometimes need more, and the guide now explains the next two steps (pointing pairs and naked pairs) and says so plainly. Two fixes while playing: placing a number now crosses it off the notes in its row, column and box (after Auto-notes, the old notes kept offering numbers that could no longer go there). And typing in the menu's search box no longer writes into the board — a 2 typed there used to land in the selected square, and Backspace erased it.

2026-10-24

I counted the starting numbers on a few hundred Expert grids and found Expert often handed you as many as Hard — now and then more than Medium. Each new puzzle is now dug a few times and the sparsest one kept, so Expert starts around 24–26 numbers and Hard around 27–29. Diagonal grids also appear instantly now (a new one could take two seconds to build). Today's daily stays exactly as it was; the change starts with tomorrow's.

From the blog

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💬 Bug, idea, or just to say hi? Tell Milo 🐨 · [email protected]