How much is 1 inch in kilometers?

First, we have to convert the English Units into Metric Units by converting inches to centimeters: 1 in. = 2.5 cm
Next, we convert centimeters to meters: 2.5/100 = 0.025 meters

Finally, we convert meters to kilometers: 0.025/1000 = 0.000025 kilometers

So, one inch equals 0.000025 kilometers, which is the same as saying that one inch equals one forty-thousandth of a kilometer (1/40,000).