sudokly
16×16
16×16 · Hard to evil

Sudoku 16×16

Hexadecimal sudoku for marathon solvers.

16×16·00:00
About 16×16

What sudoku 16×16 feels like.

Sudoku 16×16 uses a 16-row by 16-column grid divided into 4×4 boxes. We use the hexadecimal characters 0 through F so digits stay single-character. The puzzle's combinatorial space is enormous. even an easy 16×16 takes 30+ minutes.

Rules

  1. Each row contains every hexadecimal digit (0–9, A–F) exactly once.
  2. Each column contains every hexadecimal digit exactly once.
  3. Each 4×4 box contains every hexadecimal digit exactly once.
Key rule
Digits 0–9 + A–F (hex) in 4×4 boxes
Difficulty range
Hard to evil
Tips
  • Pencil marks aren't optional. every empty cell has up to 16 candidates.
  • Hidden singles are still the most efficient first scan, but they're rarer in 16×16.
  • Take breaks. 16×16 solves often run over an hour.

Sudoku 16×16 FAQ

Why hex digits in 16×16 sudoku?

Because each cell holds a value 0–15, and hex (0–9, A–F) keeps it to one character. Some publications use the numbers 1–16 instead, but that doubles cell width.

How long does a 16×16 take?

Easy ones are 30–45 minutes; hard takes several hours. Most solvers do them across multiple sessions.

Are 16×16 puzzles unique?

Yes, all Sudokly 16×16 puzzles are verified unique.

Do classic techniques work on 16×16?

Yes. naked singles, hidden singles, pairs, triples, X-wing all generalise. The candidate space is just much larger.

Is there a 16×16 daily puzzle?

Not yet. Our daily rotation is 9×9 only at launch. 16×16 is a planned addition once the engine is stable.