Master · 15×15 grid
15×15 Thermometer Puzzle
The 15×15 thermometer puzzle is our largest grid, with more than 50 thermometers and 225 cells. It is a marathon that rewards careful bookkeeping and patience. The puzzle is generated in the background, and your progress is saved automatically.
About 15×15 thermometer puzzles
| Grid | 15 × 15 = 225 cells |
|---|---|
| Difficulty | Master |
| Typical solve time | 25–60+ minutes |
| Shapes | Straight or curved thermometers |
| Solutions | Exactly one, checked by our solver |
Tips for 15×15 puzzles
- Work in regions: settle a corner fully before moving on.
- Turn on Highlight rule breaks to catch slips early on such a big board.
- Print it from the Print button if you prefer pen and paper.
New to the game? Read how to play, or study the solving strategies. Other sizes: 4×4 · 6×6 · 8×8 · 10×10 · 12×12.