How to Play Thermometers
Fill thermometer shapes with mercury from the bulb end upward. Row and column clues tell you how many cells are filled in each line.
Try it now — Easy 7x7 →The Rules
- Fill thermometers with mercury starting from the bulb end — no gaps allowed
- Mercury always flows from the bulb; you cannot fill the tip without filling everything below it
- Row clues show the total filled cells crossing each row; column clues show the same for columns
- Every thermometer is either partially or fully filled from the bulb end
Available in 3 sizes (5x5, 7x7, 9x9) and 3 difficulty levels (easy, normal, hard).
See It in Action
Click to fill thermometers from the bulb upward — row and column clues tell how many cells are filled
How to Play
- Use row and column clues to calculate how many cells must be filled in each line
- For each thermometer crossing a constrained row, find the minimum fill level consistent with the clue
- If a row clue equals the total thermometer cells in that row, all those cells are filled
- Combine row and column constraints to fix each thermometer's exact mercury level
Pro Tips
Remember: mercury fills from the bulb — a half-filled thermometer is always filled from one specific end
A column with a high clue and few thermometers crossing it forces those thermometers to be mostly full
Work both row and column directions simultaneously — each constraint reduces the others
Frequently Asked Questions
What is the Thermometers puzzle?
The grid contains thermometer shapes. You fill them with mercury starting from the bulb end. Mercury always fills from the bottom/left up without gaps. Numbers on rows and columns tell you how many cells are filled.
Choose Your Challenge
Start with easy to learn the rules, then progress to harder difficulties.