Free printable · With answers
Free Printable Thermometer Puzzles
Shade the mercury in each thermometer, always starting at the bulb, so the numbers outside the grid match.
About Thermometer Puzzles
A thermometer puzzle fills a grid with thermometers of different lengths. The numbers above the columns and beside the rows say how many cells are filled in each. Mercury always rises from the bulb with no gaps, so a thermometer can be empty, partly filled or full.
How to solve Thermometers
- Row and column counts: The number beside a row, or above a column, is how many of its cells are filled.
- Start at the bulb: Mercury begins at the round bulb and rises toward the flat end.
- No gaps: A cell can only be filled if every cell between it and the bulb is filled too.
- Any level: A thermometer can be empty, partly filled or completely full.
Reading the sheet
- Numbers on top count filled cells in each column; numbers on the left count each row.
- Shaded cells in the answer key are the mercury.
Questions
Where do I start a thermometer puzzle?
Look for rows or columns with a 0 (nothing filled) or a count equal to the grid size (everything filled), then follow each thermometer back to its bulb.
How do I save these as a PDF?
Press Print / Save PDF and choose "Save as PDF" as the printer. Press New puzzles for a different set; there are 500 to draw from.
Play Thermometers online
Solve with undo, hints and a fresh puzzle whenever you want, right in your browser.