Kilometers per Hour (km/h) to Miles per Hour (mph) Conversion Calculator

km/h to mph Conversion Calculator

Click on the following link if you want to convert miles per hour to kilometers per hour – mph to km/h

History

The kilometer per hour (km/h) is a metric speed unit introduced with the metric system in the late 18th century.
It measures how many kilometers are traveled in one hour and is used worldwide in traffic, science, and sports.

The mile per hour (mph) originates from the Imperial system and was used long before the metric system existed.
It measures the distance (in miles) covered in an hour and remains standard in the United States, the U.K., and a few Caribbean countries.

The key relationship:

1 mile = 1.609 kilometers

So when converting between km/h and mph, this constant is the foundation.

Common Usage

• km/h is used in Europe, Asia, Africa, and most of the world on road signs and speedometers.
• mph is used mainly in the U.S. and U.K..

For example, if your car’s speedometer shows 100 km/h, that’s about 62 mph.

Conversion Formula

To convert kilometers per hour to miles per hour:

mph = km/h ÷ 1.609

Example:

Convert 120 km/h to mph.

120 ÷ 1.609 = 74.56 mph

So, 120 km/h is approximately 75 mph.

Conversion Table

Interesting Facts

1. The world land speed record (ThrustSSC in 1997) was 1,228 km/h, or 763 mph.
2. Most European highways have speed limits between 120–130 km/h.
3. Formula 1 cars can exceed 370 km/h (230 mph) on long straights.

Frequently Asked Questions

1. How many mph are in 1 km/h?
0.621 mph.

2. How do I convert km/h to mph?
Divide by 1.609.

3. What’s faster, 100 km/h or 100 mph?
100 mph is faster (equal to 161 km/h).

4. Why does the U.S. still use mph?
Because the Imperial system remains in use for most measurements.

5. Is 60 mph the same as 100 km/h?
Almost — 60 mph equals 96.56 km/h.

Quiz

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