Inches of Rain to millimeters of rain converter
Convert inches of rain to millimeters of rain instantly with a fast in rain to mm rain calculator.
About converting inches of rain to millimeters of rain
Why this weather conversion comes up often
US weather reports often describe rainfall in inches, while many forecast models, international services, and hydrology references use millimeters. That makes inches to mm rain a practical conversion whenever you want to compare local storm totals with international or technical weather sources.
Rainfall conversion formula
To convert inches of rain to millimeters, multiply by 25.4. That means 1 inch of rain equals 25.4 mm, half an inch is 12.7 mm, and 2 inches equals 50.8 mm. Those benchmarks make it easier to compare rainfall totals across different forecast systems.
Where this conversion helps
The conversion is useful for storm tracking, flood guidance, agricultural planning, and comparing rainfall totals from multiple sources. A dedicated inches to mm rain converter helps translate weather data quickly without leaving the forecast workflow.
Formula
live referenceUse the same conversion rule shown below in the widget, examples, and table on this page.
millimeter of rain = inch of rain x 25.4
1 in rain x 25.4 = 25.4 mm rain
Example conversions
30 presetsQuick reference values for the most common inches of rain to millimeters of rain lookups.
0.01 in rain
0.254 mm rain
0.05 in rain
1.27 mm rain
0.1 in rain
2.54 mm rain
0.25 in rain
6.35 mm rain
0.5 in rain
12.7 mm rain
0.75 in rain
19.05 mm rain
1 in rain
25.4 mm rain
1.25 in rain
31.75 mm rain
1.5 in rain
38.1 mm rain
2 in rain
50.8 mm rain
2.5 in rain
63.5 mm rain
3 in rain
76.2 mm rain
4 in rain
101.6 mm rain
5 in rain
127 mm rain
6 in rain
152.4 mm rain
8 in rain
203.2 mm rain
10 in rain
254 mm rain
12 in rain
304.8 mm rain
15 in rain
381 mm rain
20 in rain
508 mm rain
25 in rain
635 mm rain
30 in rain
762 mm rain
40 in rain
1,016 mm rain
50 in rain
1,270 mm rain
60 in rain
1,524 mm rain
75 in rain
1,905 mm rain
100 in rain
2,540 mm rain
125 in rain
3,175 mm rain
150 in rain
3,810 mm rain
200 in rain
5,080 mm rain
Conversion table
30 rows| in rain | mm rain |
|---|---|
| 0.01 in rain | 0.254 mm rain |
| 0.05 in rain | 1.27 mm rain |
| 0.1 in rain | 2.54 mm rain |
| 0.25 in rain | 6.35 mm rain |
| 0.5 in rain | 12.7 mm rain |
| 0.75 in rain | 19.05 mm rain |
| 1 in rain | 25.4 mm rain |
| 1.25 in rain | 31.75 mm rain |
| 1.5 in rain | 38.1 mm rain |
| 2 in rain | 50.8 mm rain |
| 2.5 in rain | 63.5 mm rain |
| 3 in rain | 76.2 mm rain |
| 4 in rain | 101.6 mm rain |
| 5 in rain | 127 mm rain |
| 6 in rain | 152.4 mm rain |
| 8 in rain | 203.2 mm rain |
| 10 in rain | 254 mm rain |
| 12 in rain | 304.8 mm rain |
| 15 in rain | 381 mm rain |
| 20 in rain | 508 mm rain |
| 25 in rain | 635 mm rain |
| 30 in rain | 762 mm rain |
| 40 in rain | 1,016 mm rain |
| 50 in rain | 1,270 mm rain |
| 60 in rain | 1,524 mm rain |
| 75 in rain | 1,905 mm rain |
| 100 in rain | 2,540 mm rain |
| 125 in rain | 3,175 mm rain |
| 150 in rain | 3,810 mm rain |
| 200 in rain | 5,080 mm rain |
About this converter
tool notesRainfall totals are easy to misread when forecast sources switch between metric and imperial reporting. One service may describe a storm in millimeters, while a local weather report uses inches of rain. This hub keeps rainfall conversion focused on that weather use case so you can compare totals, brief conditions, and read hydrology-style references without second-guessing what the number means.
How many millimeters of rain are in 1 inch?
1 inch of rain equals exactly 25.4 millimeters of rain.
What is the formula to convert inches to mm rain?
Multiply inches of rain by 25.4 to convert them to millimeters of rain.
Why convert inches of rain to millimeters?
It helps compare storm totals with international forecasts, hydrology products, and weather datasets that use metric rainfall units.