To calculate average speed, divide the total distance traveled by the total elapsed time:
Average Speed = Total Distance ÷ Total Time
For example, if you travel:
180 miles
in:
3 hours
then:
Average Speed = 180 ÷ 3
Average Speed = 60 mph
The important word is total. If your journey includes different speeds, multiple segments, or stops, calculate the total distance and total time first rather than simply averaging the individual speed values.
What Is Average Speed?
Average speed describes how much total distance is traveled per unit of elapsed time over an entire journey.
The formula is:
Average Speed = Total Distance ÷ Total Time
In symbols:
vavg = dtotal ÷ ttotal
where:
- vavg = average speed;
- dtotal = total distance traveled;
- ttotal = total elapsed time.
Average speed is a scalar quantity, meaning it describes magnitude without direction.
How Do You Calculate Average Speed?
Use three basic steps.
Step 1: Find the Total Distance
Add all distances traveled.
For example:
Segment 1 = 80 miles
Segment 2 = 120 miles
Then:
Total Distance = 80 + 120
Total Distance = 200 miles
Step 2: Find the Total Time
Add the time spent traveling over the same interval.
Suppose:
Segment 1 = 2 hours
Segment 2 = 2 hours
Then:
Total Time = 2 + 2
Total Time = 4 hours
Step 3: Divide Total Distance by Total Time
Average Speed = 200 ÷ 4
Average Speed = 50 mph
This is the fundamental method regardless of how many segments the trip contains.
What Is the Average Speed Formula?
The formula is:
Average Speed = Total Distance ÷ Total Elapsed Time
This is the standard physics definition of average speed.
It is part of the broader relationship explained in our Distance, Speed and Time Formula guide:
Distance = Speed × Time
Speed = Distance ÷ Time
Time = Distance ÷ Speed
Is Average Speed the Same as Speed?
Not always.
“Speed” can refer to several related quantities.
Instantaneous Speed
How fast an object is moving at one specific moment.
A car speedometer approximately shows instantaneous speed.
Average Speed
Total distance divided by total elapsed time over a selected interval.
For example, your speedometer may show:
70 mph
on a highway.
But if your complete trip includes slower roads and stops, your average speed might be:
48 mph
OpenStax makes the same distinction between average and instantaneous speed.
Average Speed Example
Suppose a car travels:
300 miles
in:
5 hours
Use:
Average Speed = Distance ÷ Time
Average Speed = 300 ÷ 5
Average Speed = 60 mph
The average speed is:
60 miles per hour
The vehicle does not need to travel at exactly 60 mph throughout the journey.
Average Speed in Kilometers Per Hour
Suppose:
Distance = 420 km
Time = 6 hours
Then:
Average Speed = 420 ÷ 6
Average Speed = 70 km/h
Average Speed in Meters Per Second
Suppose an athlete travels:
1,000 meters
in:
125 seconds
Then:
Average Speed = 1,000 ÷ 125
Average Speed = 8 m/s
How Do You Calculate Average Travel Speed?
For a complete trip:
Average Travel Speed = Total Travel Distance ÷ Total Elapsed Time
For example:
Distance = 250 miles
Trip Time = 5 hours
Then:
Average Travel Speed = 250 ÷ 5
Average Travel Speed = 50 mph
If the trip time includes stops, the result includes the effect of those stops.
If you only use moving time, you calculate a moving average instead.
Should Stops Be Included in Average Speed?
It depends on the time interval you want to describe.
Suppose:
Distance = 200 miles
Driving Time = 3 hours
Lunch Stop = 1 hour
Average Over the Entire Trip
Total elapsed time:
3 + 1 = 4 hours
Then:
Average Speed = 200 ÷ 4
Average Speed = 50 mph
Moving Average Speed
If you exclude the lunch stop:
Average Moving Speed = 200 ÷ 3
≈ 66.67 mph
Both calculations can be valid, but they describe different intervals.
Always state whether stopped time is included.
Why Isn't Average Speed Always the Average of Two Speeds?
Because the amount of time spent at each speed matters.
Suppose you travel:
60 miles at 30 mph
then:
60 miles at 60 mph
A simple arithmetic average gives:
(30 + 60) ÷ 2 = 45 mph
But that is not the correct trip average.
First calculate the time for each segment.
At 30 mph:
Time = 60 ÷ 30
Time = 2 hours
At 60 mph:
Time = 60 ÷ 60
Time = 1 hour
Total distance:
120 miles
Total time:
3 hours
Therefore:
Average Speed = 120 ÷ 3
Average Speed = 40 mph
The correct average speed is 40 mph, not 45 mph.
OpenStax uses this same type of example to show why average speed should not automatically be calculated by averaging individual speeds.
When Can You Simply Average Two Speeds?
A simple arithmetic average works when the object spends equal amounts of time at each speed.
Suppose:
1 hour at 40 mph
and:
1 hour at 60 mph
Distance during first hour:
40 miles
Distance during second hour:
60 miles
Total distance:
100 miles
Total time:
2 hours
Then:
Average Speed = 100 ÷ 2
Average Speed = 50 mph
Arithmetic average:
(40 + 60) ÷ 2
= 50 mph
The values match because the time spent at each speed is equal.
What if the Distances Are Equal?
If equal distances are traveled at two different speeds, the arithmetic mean is generally wrong.
For two equal-distance sections with speeds:
v₁
and:
v₂
the average speed is:
Average Speed = (2 × v₁ × v₂) ÷ (v₁ + v₂)
This is the harmonic mean of the two speeds.
For:
v₁ = 30 mph
v₂ = 60 mph
calculate:
Average Speed = (2 × 30 × 60) ÷ (30 + 60)
Average Speed = 3,600 ÷ 90
Average Speed = 40 mph
Why Do Equal Distances Require a Different Average?
Because the slower segment takes more time.
Consider equal distances of:
60 miles
At:
30 mph
the trip takes:
2 hours
At:
60 mph
the same distance takes:
1 hour
You spend twice as long at the slower speed.
The slower speed therefore has a greater effect on the total trip average.
Average Speed for Multiple Segments
For any number of trip segments:
Average Speed = Total Distance ÷ Total Time
Suppose:
Segment 1
50 miles in 1 hour
Segment 2
100 miles in 2 hours
Segment 3
90 miles in 1.5 hours
Total distance:
50 + 100 + 90 = 240 miles
Total time:
1 + 2 + 1.5 = 4.5 hours
Then:
Average Speed = 240 ÷ 4.5
Average Speed ≈ 53.33 mph
You do not need to average the individual segment speeds.
Average Speed With Three Different Speeds
Suppose you travel:
30 miles at 30 mph
60 miles at 60 mph
80 miles at 40 mph
Calculate each time.
First segment:
30 ÷ 30 = 1 hour
Second segment:
60 ÷ 60 = 1 hour
Third segment:
80 ÷ 40 = 2 hours
Total distance:
30 + 60 + 80 = 170 miles
Total time:
1 + 1 + 2 = 4 hours
Average speed:
170 ÷ 4
42.5 mph
How Do You Calculate Average Speed When Times Are Given?
If you know the speed and time of each segment, calculate each segment's distance first:
Distance = Speed × Time
Then add all distances and times.
Suppose:
2 hours at 40 mph
and:
3 hours at 60 mph
First distance:
40 × 2 = 80 miles
Second distance:
60 × 3 = 180 miles
Total distance:
260 miles
Total time:
5 hours
Average speed:
260 ÷ 5
52 mph
Weighted Average Speed
When different speeds apply for different amounts of time, average speed is effectively a time-weighted average.
For speeds:
v₁, v₂, …
used for times:
t₁, t₂, …
then:
Average Speed = (v₁t₁ + v₂t₂ + …) ÷ (t₁ + t₂ + …)
This works because:
v × t = distance
so the numerator is simply total distance.
Example of a Time-Weighted Average
Suppose:
40 mph for 2 hours
and:
70 mph for 1 hour
Distance:
40 × 2 = 80 miles
plus:
70 × 1 = 70 miles
Total:
150 miles
Total time:
3 hours
Then:
Average Speed = 150 ÷ 3
Average Speed = 50 mph
The simple average:
(40 + 70) ÷ 2 = 55 mph
would be incorrect because the speeds were not maintained for equal amounts of time.
Can Average Speed Be Higher Than the Highest Speed?
No.
If all segment times are positive, the average speed must lie between the lowest and highest speeds used during the journey.
For example, if you travel only at speeds between:
30 mph
and:
70 mph
your average speed cannot exceed 70 mph or fall below 30 mph unless stopped time is included.
If stopped intervals are counted as:
0 mph
the overall average can fall below the lowest moving speed.
Can Average Speed Be Zero?
Yes, if no distance is traveled during the measured interval.
If:
Total Distance = 0
then:
Average Speed = 0 ÷ Time
Average Speed = 0
However, a round trip that returns to the starting location can still have positive average speed because distance traveled is not zero.
Average Speed vs Average Velocity
Average speed and average velocity are different.
Average Speed
Total Distance ÷ Total Time
Average Velocity
Displacement ÷ Total Time
Velocity also has direction.
Suppose you travel:
5 miles east
then:
5 miles west
Total distance:
10 miles
Final displacement:
0 miles
If the trip takes:
2 hours
then:
Average Speed = 10 ÷ 2
Average Speed = 5 mph
but:
Average Velocity = 0 ÷ 2
Average Velocity = 0
OpenStax explicitly distinguishes average speed from average velocity in this way.
Average Speed vs Instantaneous Speed
Average speed describes an entire interval.
Instantaneous speed describes a particular moment.
For example:
At 10:15 AM your car might be traveling:
65 mph
but across the complete trip your average speed might be:
52 mph
because of lower-speed roads, intersections, and stops.
Average Speed vs Pace
Speed measures:
Distance ÷ Time
Pace measures:
Time ÷ Distance
For example:
6 mph
corresponds to:
10 minutes per mile
because:
60 minutes ÷ 6 miles = 10 min/mile
CalculatorSoup similarly defines speed as distance divided by time and pace as time divided by distance.
How Do You Convert Average Speed to Pace?
For mph:
Pace in minutes per mile = 60 ÷ Speed in mph
For:
Average Speed = 5 mph
then:
Pace = 60 ÷ 5
Pace = 12 minutes per mile
How Do You Convert Pace to Average Speed?
Use:
Speed in mph = 60 ÷ Pace in minutes per mile
For:
Pace = 15 minutes per mile
then:
Speed = 60 ÷ 15
Speed = 4 mph
Average Speed for a Road Trip
For road travel, use:
Average Road Speed = Total Driving Distance ÷ Total Elapsed Time
Suppose:
Driving Distance = 360 miles
Elapsed Trip Time = 6.5 hours
Then:
Average Speed = 360 ÷ 6.5
Average Speed ≈ 55.38 mph
The total distance should normally be the actual road-route distance rather than the straight-line separation between the cities.
Use the Driving Distance Calculator when you need the road mileage itself.
Why Should Road Trips Use Driving Distance?
A car travels along roads rather than the shortest geographic line between two coordinates.
Suppose:
Straight-line distance = 180 miles
but:
Driving distance = 220 miles
and:
Travel time = 4 hours
Using straight-line distance:
180 ÷ 4 = 45 mph
Using road distance:
220 ÷ 4 = 55 mph
The second value better represents average vehicle speed along the actual route.
Does Traffic Lower Average Speed?
Usually, yes.
If distance stays approximately the same while elapsed time increases, average speed falls.
For example:
Without congestion:
100 miles ÷ 2 hours = 50 mph
With congestion:
100 miles ÷ 2.5 hours = 40 mph
The extra travel time reduces the trip average.
Do Rest Stops Lower Average Travel Speed?
Yes, if they are included in total elapsed time.
Suppose:
Driving distance = 240 miles
Moving time = 4 hours
Breaks = 1 hour
Moving average:
240 ÷ 4 = 60 mph
Whole-trip average:
240 ÷ 5 = 48 mph
The correct value depends on what you are trying to measure.
How Do You Calculate Average Walking Speed?
Use:
Average Walking Speed = Walking Distance ÷ Walking Time
For example:
Distance = 4 miles
Time = 1 hour 20 minutes
Convert:
20 minutes = 20 ÷ 60 = 0.3333 hours
Total:
1.3333 hours
Then:
Average Walking Speed = 4 ÷ 1.3333
≈ 3 mph
For actual pedestrian route distance, use the Walking Route Distance Calculator.
How Do You Calculate Average Running Speed?
Suppose:
Distance = 10 km
Time = 50 minutes
Convert:
50 ÷ 60 ≈ 0.83333 hours
Then:
Average Speed = 10 ÷ 0.83333
≈ 12 km/h
How Do You Calculate Average Cycling Speed?
Suppose:
Distance = 45 miles
Time = 3 hours
Then:
Average Speed = 45 ÷ 3
Average Speed = 15 mph
How Do You Calculate Average Speed With Minutes?
Convert minutes into hours if you want mph or km/h.
Suppose:
Distance = 40 miles
Time = 48 minutes
Convert:
48 ÷ 60 = 0.8 hours
Then:
Average Speed = 40 ÷ 0.8
Average Speed = 50 mph
How Do You Calculate Average Speed With Seconds?
If distance is in meters and time is in seconds:
Average Speed in m/s = Meters ÷ Seconds
For example:
500 meters ÷ 80 seconds
= 6.25 m/s
No conversion is required because the desired unit is meters per second.
How Do You Convert MPH to KM/H?
Use:
km/h = mph × 1.609344
For example:
50 mph × 1.609344
≈ 80.47 km/h
How Do You Convert KM/H to MPH?
Use:
mph = km/h × 0.621371
For example:
80 km/h × 0.621371
≈ 49.71 mph
How Do You Convert M/S to KM/H?
Use:
km/h = m/s × 3.6
For example:
10 m/s × 3.6
= 36 km/h
Average Speed Unit Reference
| Distance | Time | Average Speed Unit |
|---|---|---|
| miles | hours | mph |
| kilometers | hours | km/h |
| meters | seconds | m/s |
| feet | seconds | ft/s |
Make sure the distance and time units match the speed unit you want.
Average Speed vs Average of Speeds: Quick Guide
| Situation | Correct Method |
|---|---|
| One trip, total distance and time known | Total distance ÷ total time |
| Equal time at two speeds | Arithmetic mean works |
| Equal distance at two speeds | Harmonic mean |
| Different distances and times | Total distance ÷ total time |
| Trip includes stops | Decide whether stop time belongs in total time |
Equal-Time Example
Travel:
2 hours at 50 mph
and:
2 hours at 70 mph
Distances:
100 miles
and:
140 miles
Total:
240 miles
Time:
4 hours
Average:
240 ÷ 4
60 mph
Arithmetic mean:
(50 + 70) ÷ 2 = 60 mph
Because the time intervals are equal, both methods agree.
Equal-Distance Example
Travel:
100 miles at 50 mph
then:
100 miles at 100 mph
Time at 50 mph:
100 ÷ 50 = 2 hours
Time at 100 mph:
100 ÷ 100 = 1 hour
Total distance:
200 miles
Total time:
3 hours
Average speed:
200 ÷ 3
≈ 66.67 mph
The arithmetic average would be:
75 mph
which is incorrect.
Round Trip With the Same Distance at Different Speeds
Suppose you drive:
120 miles outward at 40 mph
and:
120 miles back at 60 mph
Outbound time:
120 ÷ 40 = 3 hours
Return time:
120 ÷ 60 = 2 hours
Total distance:
240 miles
Total time:
5 hours
Average speed:
240 ÷ 5
48 mph
Again, the simple average:
(40 + 60) ÷ 2 = 50 mph
is wrong.
Round Trip and Average Velocity
If you return to the exact starting point:
Displacement = 0
Therefore:
Average Velocity = 0
But total distance is positive, so average speed remains positive.
For the previous example:
Total Distance = 240 miles
Total Time = 5 hours
Average speed:
48 mph
Average velocity:
0 mph in terms of net displacement per hour over the complete round trip.
What Is the Harmonic Mean Formula for Two Equal Distances?
For equal-distance segments:
Average Speed = 2v₁v₂ ÷ (v₁ + v₂)
For example:
v₁ = 40 mph
v₂ = 60 mph
Then:
Average Speed = (2 × 40 × 60) ÷ (40 + 60)
= 4,800 ÷ 100
= 48 mph
This matches the full total-distance/total-time calculation.
Do You Need the Harmonic Mean Formula?
Not necessarily.
The safest general method is always:
- calculate total distance;
- calculate total time;
- divide.
The harmonic mean is simply a shortcut for the special case where two equal distances are traveled at different speeds.
Can You Average More Than Two Speeds?
Yes, but again the weighting matters.
Do not automatically calculate:
(v₁ + v₂ + v₃) ÷ 3
unless equal time is spent at all three speeds.
The general method remains:
Average Speed = Total Distance ÷ Total Time
Can Average Speed Include Zero-Speed Periods?
Yes.
If an object stops during the measured interval, that stop contributes:
0 distance
but still adds time.
This lowers the average speed.
For example:
Travel:
60 miles in 1 hour
Stop:
1 hour
Total:
60 miles in 2 hours
Average speed:
30 mph
What Happens if Total Time Is Zero?
The formula:
Average Speed = Total Distance ÷ Total Time
cannot divide by zero.
If nonzero distance is claimed to occur in zero time, the average speed is undefined in ordinary finite-speed calculations.
What Happens if Total Distance Is Zero?
If:
Total Distance = 0
and elapsed time is positive:
Average Speed = 0
However, remember that distance is not the same as displacement.
A traveler who moves away and returns has positive total distance even though displacement is zero.
Is Average Speed Always Positive?
Average speed is nonnegative because distance and elapsed time are nonnegative quantities.
It can be:
0
or a positive value.
Direction does not make speed negative.
Signed direction belongs to velocity.
Average Speed vs Average Velocity Quick Comparison
| Quantity | Formula | Direction? |
|---|---|---|
| Average speed | Total distance ÷ total time | No |
| Average velocity | Displacement ÷ total time | Yes |
This distinction is fundamental in physics.
Average Speed vs Driving Speed Estimate
A routing system may provide an estimated trip duration based on its road model.
You can derive an implied average route speed using:
Average Route Speed = Route Distance ÷ Estimated Route Time
But that does not mean the vehicle will travel at one constant speed.
The route estimate can reflect multiple road classes and speed assumptions.
Our How Driving Distance Is Calculated guide explains how routing differs from simple straight-line mathematics.
Average Speed vs Speed Limit
Average speed is usually lower than the highest posted speed limit on a trip.
A route can include:
- slower roads;
- intersections;
- traffic lights;
- congestion;
- stops.
So you should not assume:
Trip Average Speed = Highway Speed Limit
These are different quantities.
How Can You Check Whether an Average Speed Answer Is Reasonable?
Check three things.
1. Units
Miles divided by hours should produce mph.
2. Range
The result should generally fall within a reasonable range for the trip.
3. Total Relationship
Multiply the average speed by total time:
Distance = Average Speed × Total Time
You should recover the total distance.
For example:
50 mph × 4 hours = 200 miles
This confirms the calculation.
Common Average Speed Mistakes
Averaging Speeds Directly
Do not automatically calculate the arithmetic mean of segment speeds.
Ignoring Time Weighting
Longer time at one speed gives that speed more influence.
Mixing Minutes and Hours
Convert time units before calculating mph or km/h.
Using Displacement Instead of Distance
Average speed uses total distance traveled.
Using Straight-Line Distance for a Road Trip
Use actual route distance for vehicle travel.
Forgetting Stops
Decide whether stopped time is part of the interval.
Confusing Average Speed With Instantaneous Speed
A speedometer reading is not the same as the trip average.
Rounding Too Early
Keep intermediate values reasonably precise and round at the end.
Average Speed Quick Reference
The main rule is:
Average Speed = Total Distance ÷ Total Time
For two equal-time speeds:
Average Speed = (v₁ + v₂) ÷ 2
For two equal-distance speeds:
Average Speed = 2v₁v₂ ÷ (v₁ + v₂)
But the universal method remains:
Total Distance ÷ Total Time
Which Speed Resource Should You Use?
| Goal | Best resource |
|---|---|
| Understand distance, speed, and time together | Distance, Speed and Time Formula |
| Calculate speed from one distance and time | How to Calculate Speed From Distance and Time |
| Calculate average speed over a full or multi-part trip | Average Speed Calculator Explained |
| Get road mileage | Driving Distance Calculator |
| Understand road-route calculation | How Driving Distance Is Calculated |
| Get actual walking-route distance | Walking Route Distance Calculator |
Frequently Asked Questions
What is the average speed formula?
Use:
Average Speed = Total Distance ÷ Total Time
How do you calculate average speed?
Add all distance traveled, add the corresponding elapsed time, then divide total distance by total time.
Is average speed the average of two speeds?
Not necessarily. A simple arithmetic average is correct only in certain cases, such as equal time spent at each speed.
What is the average speed for equal distances at 30 mph and 60 mph?
The correct average is 40 mph, not 45 mph.
What is the average speed for equal distances at 40 mph and 60 mph?
The correct average is 48 mph.
Should stops be included in average speed?
Include them if you are calculating the average over the entire elapsed trip. Exclude them if you specifically want moving average speed.
Is average speed the same as average velocity?
No. Average speed uses total distance, while average velocity uses displacement and includes direction.
Can average speed be zero?
Yes, if no distance is traveled during the measured interval.
Can average speed be negative?
No. Speed is a scalar magnitude and is nonnegative.
What distance should I use for a road trip?
Use actual driving-route distance when calculating average road speed.
Why is the average of 30 mph and 60 mph sometimes not 45 mph?
If equal distances are traveled at those speeds, more time is spent at the slower speed. The correct average is therefore 40 mph.
What is average travel speed?
Average travel speed is the total trip distance divided by the total elapsed travel time for the interval being measured.