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| Inches | Millimetres | Rainfall context |
|---|---|---|
| 0.1 in | 2.5 mm | Light shower |
| 0.5 in | 12.7 mm | Steady rain |
| 1 in | 25.4 mm | Heavy rain |
| 2 in | 50.8 mm | Flood risk |
| 4 in | 101.6 mm | Extreme rainfall |
Inches are commonly used to measure rainfall in the United States, while millimeters are the global standard. Converting between these units allows for easy comparison of precipitation data.
Converting inches of rainfall to millimetres is essential when reading US weather and climate data in metric terms, or for anyone working with international rainfall records. Because both units express the same depth of accumulated water, the conversion is a single fixed multiplier: one inch equals exactly 25.4 millimetres. This matters for interpreting storm totals, drought figures, and irrigation needs, where the difference between a half inch and two inches of rain is the difference between a pleasant shower and a flood warning. This converter gives instant, exact results with helpful real-world context.
To convert inches to millimeters, multiply by 25.4. This tool performs the conversion instantly for accurate rainfall measurement.