| Distance |
|
|---|---|
| Time |
h
m
s
|
| Metric | Value |
|---|---|
| Average speed (km/h) | |
| Average speed (mph) |
Average speed measures how fast you moved across an entire journey, folding every leg into one steady figure. Delivery drivers auditing routes, commuters comparing door to door options, and coaches reviewing athlete training sessions all rely on that single honest number.
Press Calculate average speed and the tool returns Average speed (km/h) and Average speed (mph) side by side. Feed in each leg of the trip with its own distance and duration, and the two outputs stay consistent across unit systems, so you can quote in either currency of speed.
The governing formula is total distance divided by total time, and it is famously not the plain average of your speeds. Legs that consume more time carry more weight, so a long slow stretch drags the result well below the midpoint of the individual speeds.
Example: you hold 100 mph for 1 hour, then 50 mph for 1 hour. Distance totals 150 miles across 2 hours, so 150 divided by 2 equals a 75 mph average. But stretch the slow leg to 2 hours and you cover 200 miles in 3 hours, just 66.7 mph, well under the 75 a naive average would predict.
Enter the distance and travel time for each segment, and prefer moving time over wall clock time whenever stopping distorts the story. A 30 minute fuel break inside a 2 hour leg cuts the average far more than most drivers expect.
Keep one unit system per leg, because mixing kilometers with hours while hoping for mph is the classic blunder. Both km/h and mph appear in the output, which makes a mismatch obvious before you act on the number.
Because time spent at each speed differs, the mean misleads you. Driving 60 mph for 3 hours and 30 mph for 1 hour gives 210 miles in 4 hours, an average of 52.5 mph, not 45.
Decide whether stops count as journey time. Including a 30 minute break in a 2 hour, 150 mile trip yields 60 mph, while excluding it yields 75 mph.
Average speed equals total distance traveled divided by total elapsed time. A 240 mile drive taking 4 hours and 30 minutes works out to 4.5 hours and therefore 53.3 mph, since 240 divided by 4.5 equals 53.3.
Yes, keep every leg in kilometers and hours and the result arrives in km/h. A 300 kilometer trip over 3.75 hours averages exactly 80 km/h, which converts to about 49.7 mph.
Only through its effect on distance and time. A car that covers 100 miles in 2 hours averages 50 mph during those hours, whether it cruised steadily or alternated hard acceleration with crawling.