42 mph is equal to approximately 67.5928 kmh.
Table of Contents
To convert miles per hour (mph) to kilometers per hour (kmh), you multiply the mph value by the conversion factor 1.60934. This factor reflects the length of a mile compared to a kilometer, allowing you to switch between these two speed units accurately.
Conversion Tool
Result in kmh:
Conversion Formula
The formula to convert miles per hour to kilometers per hour is:
kmh = mph × 1.60934
This formula works because 1 mile equals approximately 1.60934 kilometers. When you multiply the speed in miles per hour by this factor, you get the equivalent speed in kilometers per hour. The multiplication adjusts the unit from miles to kilometers, preserving the speed value’s meaning.
For example, converting 42 mph:
- Start with 42 mph.
- Multiply by 1.60934: 42 × 1.60934 = 67.59228 kmh.
- Result is approximately 67.5923 kmh when rounded to four decimals.
Conversion Example
Let’s convert 55 mph to kmh:
- Begin with 55 mph.
- Multiply by 1.60934 to convert miles to kilometers: 55 × 1.60934 = 88.5137 kmh.
- The answer is about 88.5137 kmh.
Another example, 30 mph:
- Take 30 mph.
- Multiply by 1.60934: 30 × 1.60934 = 48.2802 kmh.
- This equals approximately 48.2802 kmh.
One more, 65 mph:
- Start with 65 mph.
- Multiply by 1.60934: 65 × 1.60934 = 104.6061 kmh.
- So, it’s about 104.6061 kmh.
Conversion Chart
| MPH | KMH |
|---|---|
| 17.0 | 27.3588 |
| 27.0 | 43.4522 |
| 37.0 | 59.5456 |
| 42.0 | 67.5928 |
| 47.0 | 75.6400 |
| 52.0 | 83.6877 |
| 57.0 | 91.7354 |
| 62.0 | 99.7831 |
| 67.0 | 107.8308 |
This chart shows mph values in the first column, and their equivalent speeds in kmh in the second column. You can find a speed in mph, then look right to see what it equals in kmh. This helps quick reference without calculation.
Related Conversion Questions
- How fast is 42 miles per hour in kilometers per hour?
- What is the km/h equivalent of 42 mph speed?
- If I drive 42 mph, how many kmh am I traveling?
- Convert 42 mph to km/h with exact formula?
- How do I change 42 mph into kmh in a quick way?
- What’s the numeric value of 42 mph in kilometers per hour?
- Is 42 mph faster than 67 km/h or slower?
Conversion Definitions
mph: Miles per hour (mph) is a unit of speed expressing the number of miles traveled in one hour. Commonly used in the United States and United Kingdom, it measures velocity based on the imperial system, where 1 mile equals 5,280 feet or 1,609.34 meters.
kmh: Kilometers per hour (kmh) measures speed as the number of kilometers traveled in one hour. It belongs to the metric system and is used worldwide except in a few countries. One kilometer equals 1,000 meters, making kmh a decimal-based speed unit.
Conversion FAQs
Why is the factor 1.60934 used to convert mph to kmh?
This factor represents the length of one mile in kilometers, which is approximately 1.60934 km. Using this number ensures the speed converted keeps the same real-world distance traveled per hour but expressed in metric units.
Can I convert kmh back to mph using the same formula?
No, converting from kmh to mph requires dividing the kmh value by 1.60934, not multiplying. This reverses the conversion, changing the metric speed back to the imperial system.
Is it okay to round the conversion result?
Rounding depends on the needed precision. For everyday use, rounding to two decimal places is fine. For scientific or technical applications, keeping more decimal places is better to reduce error.
Does temperature or altitude affect mph to kmh conversion?
No, the conversion between mph and kmh is purely mathematical and based on distance units. External factors like temperature or altitude do not influence this conversion.
Why do some calculators give slightly different results?
Minor differences come from rounding the conversion factor or intermediate steps. Some use 1.609 or 1.61 instead of 1.60934, causing small variations in the final number.