42 mph is equal to approximately 67.5928 kmh.
To convert 42 miles per hour (mph) into kilometers per hour (kmh), multiply the value by 1.60934. This is because one mile equals 1.60934 kilometers; so by multiplying 42 by this factor, we get the equivalent speed in kilometers per hour.
Conversion Tool
Result in kmh:
Conversion Formula
The formula to convert miles per hour to kilometers per hour is:
kmh = mph × 1.60934
Why this works: Since 1 mile equals approximately 1.60934 kilometers, multiplying the speed given in miles per hour by this conversion factor changes the unit from miles to kilometers without changing the speed’s meaning.
Example calculation for 42 mph:
- Start with 42 mph.
- Multiply by 1.60934: 42 × 1.60934 = 67.59228 kmh.
- The result is approximately 67.5923 kmh.
Conversion Example
- Convert 30 mph to kmh:
- Multiply 30 by 1.60934.
- 30 × 1.60934 = 48.2802 kmh.
- So, 30 mph is about 48.2802 kmh.
- Convert 55 mph to kmh:
- Multiply 55 by 1.60934.
- 55 × 1.60934 = 88.5137 kmh.
- This means 55 mph equals roughly 88.5137 kmh.
- Convert 10 mph to kmh:
- Multiply 10 by 1.60934.
- 10 × 1.60934 = 16.0934 kmh.
- Therefore, 10 mph corresponds to about 16.0934 kmh.
- Convert 65 mph to kmh:
- Multiply 65 by 1.60934.
- 65 × 1.60934 = 104.606 kmh.
- Hence, 65 mph equals approximately 104.606 kmh.
Conversion Chart
The chart below shows selected mph values between 17.0 and 67.0, converted into kmh. The left column is miles per hour, and the right column shows the equivalent in kilometers per hour. You can use this chart to quickly find approximate kmh values without calculation.
| mph | kmh |
|---|---|
| 17.0 | 27.3588 |
| 22.0 | 35.4055 |
| 27.0 | 43.4522 |
| 32.0 | 51.4989 |
| 37.0 | 59.5456 |
| 42.0 | 67.5923 |
| 47.0 | 75.639 |
| 52.0 | 83.6857 |
| 57.0 | 91.7324 |
| 62.0 | 99.7791 |
| 67.0 | 107.8258 |
Related Conversion Questions
- How fast is 42 mph in kilometers per hour exactly?
- What would 42 miles per hour convert to in km/h for driving speed?
- Is 42 mph equivalent to over 60 kmh?
- Can I convert 42 mph to kmh using a simple formula?
- What speed does 42 mph correspond to on a European speedometer?
- How to quickly convert 42 mph into kilometers per hour without a calculator?
- Does 42 mph equal 67 kmh or more?
Conversion Definitions
mph: Miles per hour (mph) measures speed by indicating how many miles are traveled in one hour. It is a unit widely used in the United States and the United Kingdom for road and vehicle speed. 1 mph equals exactly 1 mile traveled over 60 minutes.
kmh: Kilometers per hour (kmh) indicates how many kilometers are covered in one hour. This unit is common in most countries for speed limits and vehicle speed. It is metric system based, using the kilometer as the basic unit of distance.
Conversion FAQs
Why multiply mph by 1.60934 to get kmh?
Because 1 mile equals 1.60934 kilometers exactly, multiplying by this factor converts the distance unit from miles to kilometers. Since speed is distance over time, changing the distance unit while keeping time constant converts mph to kmh.
Can I just round 1.60934 to 1.6 for quick estimates?
Yes, rounding to 1.6 is common for simpler mental math and gives a close estimate. However, this introduces a small error that might add up in precise calculations or longer distances/speeds.
Is the conversion factor always the same for mph to kmh?
Yes, the conversion factor 1.60934 is a constant because it depends on the fixed length of one mile compared to one kilometer, which does not change with time or context.
How to convert kmh back to mph?
To convert kilometers per hour to miles per hour, divide the kmh value by 1.60934. This reverses the multiplication used in mph to kmh conversion.
Are mph and kmh used differently in various countries?
Yes, mph is common in the US and UK, while kmh is used in most other countries. Vehicle speedometers and road signs reflect these units, requiring conversions when driving internationally.