Distance, speed, and time are related by three simple formulas:
Distance = Speed × Time
Speed = Distance ÷ Time
Time = Distance ÷ Speed
If you know any two of these quantities, you can calculate the third as long as the units are compatible.
For example, traveling at 60 miles per hour for 2 hours gives:
Distance = 60 × 2
Distance = 120 miles
These formulas are useful in physics, road-trip planning, walking and running calculations, travel estimates, and many everyday distance problems.
What Is the Distance Speed Time Formula?
The fundamental relationship is:
Distance = Speed × Time
This can be rearranged to calculate speed:
Speed = Distance ÷ Time
or time:
Time = Distance ÷ Speed
These three equations describe the same mathematical relationship.
If:
- distance is known;
- speed is known;
you can find time.
If:
- distance is known;
- time is known;
you can find speed.
If:
- speed is known;
- time is known;
you can find distance.
What Do Distance, Speed and Time Mean?
Distance
Distance measures how much length has been traveled.
Common units include:
- miles;
- kilometers;
- meters;
- feet.
Speed
Speed measures the distance traveled per unit of time.
Common units include:
- miles per hour (mph);
- kilometers per hour (km/h);
- meters per second (m/s);
- feet per second (ft/s).
Time
Time measures the duration of travel.
Common units include:
- seconds;
- minutes;
- hours.
The units must work together correctly when using the formulas.
What Is the Formula for Distance?
Use:
Distance = Speed × Time
For example:
Speed = 55 mph
Time = 3 hours
Then:
Distance = 55 × 3
Distance = 165 miles
The vehicle travels 165 miles.
CalculatorSoup uses the same relationship, written as d = st, where distance equals speed multiplied by time.
What Is the Formula for Speed?
Use:
Speed = Distance ÷ Time
For example:
Distance = 180 miles
Time = 3 hours
Then:
Speed = 180 ÷ 3
Speed = 60 mph
The average speed for the trip is 60 miles per hour.
Our dedicated How to Calculate Speed From Distance and Time guide covers this calculation in more detail.
What Is the Formula for Time?
Use:
Time = Distance ÷ Speed
For example:
Distance = 240 miles
Speed = 60 mph
Then:
Time = 240 ÷ 60
Time = 4 hours
At a constant or average speed of 60 mph, a 240-mile trip takes 4 hours.
This is the basic travel time formula.
Distance Speed Time Formula Triangle
A common memory aid is the distance-speed-time triangle:
Distance
above:
Speed × Time
This helps you remember the three rearrangements.
Cover the quantity you want to calculate.
If you cover Distance, you are left with:
Speed × Time
If you cover Speed, you are left with:
Distance ÷ Time
If you cover Time, you are left with:
Distance ÷ Speed
The triangle is only a memory aid. The actual mathematics comes from the same equation:
Distance = Speed × Time
How Do You Calculate Distance From Speed and Time?
Suppose a car travels at:
70 mph
for:
2.5 hours
Use:
Distance = Speed × Time
Substitute:
Distance = 70 × 2.5
Distance = 175 miles
So the car travels 175 miles.
How Do You Calculate Speed From Distance and Time?
Suppose a cyclist travels:
45 miles
in:
3 hours
Use:
Speed = Distance ÷ Time
Then:
Speed = 45 ÷ 3
Speed = 15 mph
The average speed is 15 mph.
How Do You Calculate Travel Time From Distance and Speed?
Suppose a trip is:
150 miles
and the average speed is:
50 mph
Use:
Time = Distance ÷ Speed
Then:
Time = 150 ÷ 50
Time = 3 hours
This is a mathematical travel-time estimate assuming the given average speed accurately represents the trip.
Why Must the Units Match?
The units must be compatible because speed already combines distance and time.
For example:
Speed = 60 miles per hour
means:
60 miles in 1 hour
If the travel time is given in minutes, you should convert the minutes to hours before multiplying.
For example:
Speed = 60 mph
Time = 30 minutes
Convert:
30 minutes = 0.5 hours
Then:
Distance = 60 × 0.5
Distance = 30 miles
Using 30 directly without converting the unit would produce the wrong answer.
How Do You Convert Minutes to Hours?
Use:
Hours = Minutes ÷ 60
For example:
90 minutes ÷ 60 = 1.5 hours
So:
90 minutes = 1.5 hours
If a vehicle travels at:
40 mph
for:
90 minutes
then:
Distance = 40 × 1.5
Distance = 60 miles
How Do You Convert Seconds to Hours?
Use:
Hours = Seconds ÷ 3,600
For example:
7,200 seconds ÷ 3,600 = 2 hours
This conversion is useful when speed is given in miles per hour or kilometers per hour.
How Do You Convert Hours to Minutes?
Use:
Minutes = Hours × 60
For example:
2.5 hours × 60 = 150 minutes
So:
2.5 hours = 150 minutes
How Do You Convert Miles Per Hour to Kilometers Per Hour?
One statute mile equals approximately:
1.609344 kilometers
So:
km/h = mph × 1.609344
For example:
60 mph × 1.609344 ≈ 96.56 km/h
Calculator.net likewise lists 1 mph as approximately 1.60935 km/h in its speed conversion table.
How Do You Convert Kilometers Per Hour to Miles Per Hour?
Use:
mph = km/h × 0.621371
For example:
100 km/h × 0.621371 ≈ 62.14 mph
This conversion is useful when comparing U.S. speed values with metric measurements.
How Do You Convert Meters Per Second to Kilometers Per Hour?
Use:
km/h = m/s × 3.6
For example:
20 m/s × 3.6 = 72 km/h
The conversion works because:
1 meter per second = 3.6 kilometers per hour
How Do You Convert Miles Per Hour to Meters Per Second?
Use approximately:
m/s = mph × 0.44704
For example:
60 mph × 0.44704 ≈ 26.82 m/s
This conversion is especially common in physics problems.
Speed Units Quick Reference
| Speed Unit | Equivalent |
|---|---|
| 1 mph | 1.609344 km/h |
| 1 mph | 0.44704 m/s |
| 1 km/h | 0.621371 mph |
| 1 km/h | 0.277778 m/s |
| 1 m/s | 3.6 km/h |
| 1 m/s | 2.23694 mph |
Use enough precision for the problem you are solving rather than rounding too early.
Distance Example in Miles and Hours
Suppose:
Speed = 65 mph
Time = 4 hours
Then:
Distance = 65 × 4
Distance = 260 miles
This is one of the simplest distance-speed-time calculations because the time is already in hours and the speed is already in miles per hour.
Distance Example With Minutes
Suppose:
Speed = 48 mph
Time = 45 minutes
First convert the time:
45 ÷ 60 = 0.75 hours
Then:
Distance = 48 × 0.75
Distance = 36 miles
The vehicle travels 36 miles.
Speed Example in Kilometers Per Hour
Suppose:
Distance = 210 km
Time = 3 hours
Then:
Speed = 210 ÷ 3
Speed = 70 km/h
The average speed is 70 kilometers per hour.
Time Example With Kilometers
Suppose:
Distance = 360 km
Speed = 90 km/h
Then:
Time = 360 ÷ 90
Time = 4 hours
Can You Use the Formula for Road Trips?
Yes, but you need to interpret the speed correctly.
For road travel:
Time = Distance ÷ Average Speed
can give a rough estimate.
However, a real road trip can include:
- traffic;
- stops;
- intersections;
- construction;
- changing speed limits;
- weather;
- rest breaks.
A constant speed of 60 mph for an entire 300-mile trip is usually an idealized assumption.
For actual road-route distance and routing-based time, use the Driving Distance Calculator.
Why Is Route Travel Time Different From Distance ÷ Speed Limit?
A posted speed limit does not equal the actual average speed over an entire trip.
Suppose:
Route Distance = 100 miles
and the highway speed limit is:
65 mph
Calculating:
100 ÷ 65 ≈ 1.54 hours
does not guarantee the trip will take about 1 hour 32 minutes.
The route may include:
- local roads;
- intersections;
- slower zones;
- stops;
- congestion.
For travel planning, average route speed matters more than the maximum posted speed.
What Is Average Speed?
Average speed is:
Average Speed = Total Distance ÷ Total Time
For example:
Total Distance = 150 miles
Total Time = 3 hours
Then:
Average Speed = 150 ÷ 3
Average Speed = 50 mph
Average speed describes the entire journey, even when the actual speed changes during the trip.
Calculator.net similarly defines speed as distance divided by time and discusses this relationship for travel calculations.
Why Isn't Average Speed Always the Average of Two Speeds?
Because the amount of time or distance 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 the actual travel times are:
60 ÷ 30 = 2 hours
and:
60 ÷ 60 = 1 hour
Total distance:
120 miles
Total time:
3 hours
So:
Average Speed = 120 ÷ 3
Average Speed = 40 mph
The correct answer is 40 mph, not 45 mph.
Our Average Speed Calculator Explained page covers this issue in detail.
Speed vs Velocity
Speed and velocity are related but not identical.
Speed is a scalar quantity. It describes how fast something moves.
Velocity includes both magnitude and direction.
For example:
60 mph
is a speed.
60 mph north
describes velocity more fully because direction is included.
For ordinary road-trip calculations, speed is usually the quantity people mean.
Distance vs Displacement
Distance measures total path length.
Displacement measures the change in position from the starting point to the ending point.
For example, if you walk:
3 miles east
then:
3 miles west
your total distance is:
6 miles
but your final displacement is:
0 miles
because you returned to your starting point.
This distinction matters in physics even though everyday travel calculations usually focus on distance.
Is Distance Always Equal to Speed × Time?
The formula:
Distance = Speed × Time
works directly when speed is constant over the time interval.
It also works with average speed when that average is defined as:
Total Distance ÷ Total Time
For motion where speed continuously changes, more advanced calculations may use calculus or divide the motion into intervals.
The simple equation is still the correct foundational relationship.
What Happens if Speed Is Zero?
If:
Speed = 0
then:
Distance = 0 × Time
so:
Distance = 0
for that interval.
But using:
Time = Distance ÷ Speed
with:
Speed = 0
would involve division by zero and is undefined for a nonzero distance.
This is an important edge case.
What Happens if Time Is Zero?
If no time passes:
Time = 0
then for finite speed:
Distance = Speed × 0
Distance = 0
Trying to calculate:
Speed = Distance ÷ 0
is undefined when the distance is nonzero.
Can Distance Be Negative?
Ordinary traveled distance is nonnegative.
You can travel:
0 miles
or a positive number of miles.
A negative value may appear in coordinate displacement or signed position calculations, but it does not represent ordinary path length.
Can Speed Be Negative?
Ordinary speed is nonnegative.
Velocity can use positive or negative signs when a coordinate direction has been defined.
For example:
+10 m/s
and:
−10 m/s
can represent opposite directions of velocity.
Both have a speed magnitude of:
10 m/s
How Do You Calculate Distance Using Average Speed?
Use:
Distance = Average Speed × Total Time
For example:
Average Speed = 52 mph
Total Time = 2.5 hours
Then:
Distance = 52 × 2.5
Distance = 130 miles
The key is that the speed value must represent the average over the same time interval.
How Do You Calculate Required Speed for a Trip?
Suppose you need to travel:
240 miles
in:
4 hours
Use:
Speed = Distance ÷ Time
Speed = 240 ÷ 4
Speed = 60 mph
You would need an average speed of 60 mph over the full four-hour interval.
That does not mean driving at exactly 60 mph every moment.
How Do You Calculate How Far You Can Travel in 30 Minutes?
First convert:
30 minutes = 0.5 hours
At:
60 mph
calculate:
Distance = 60 × 0.5
Distance = 30 miles
At:
40 mph
calculate:
Distance = 40 × 0.5
Distance = 20 miles
This relationship is useful for rough travel-range estimates.
How Far Can You Travel in One Hour?
Numerically, the distance traveled in one hour equals the speed expressed per hour.
At:
30 mph → 30 miles in 1 hour
55 mph → 55 miles in 1 hour
70 mph → 70 miles in 1 hour
This assumes the stated speed is maintained for the entire hour.
How Long Does It Take to Travel 100 Miles?
The answer depends on speed.
Use:
Time = 100 ÷ Speed
Examples:
| Average Speed | Time for 100 Miles |
|---|---|
| 25 mph | 4 hours |
| 40 mph | 2.5 hours |
| 50 mph | 2 hours |
| 60 mph | 1 hr 40 min |
| 75 mph | 1 hr 20 min |
These are ideal mathematical values based on constant average speed and do not include additional stops.
How Long Does It Take to Drive 300 Miles at 60 MPH?
Use:
Time = Distance ÷ Speed
Time = 300 ÷ 60
Time = 5 hours
The mathematical travel time is 5 hours.
Actual road-trip duration can be longer because of stops or route conditions.
How Far Do You Travel at 70 MPH for 30 Minutes?
Convert:
30 minutes = 0.5 hours
Then:
Distance = 70 × 0.5
Distance = 35 miles
How Long Does It Take to Walk 3 Miles at 3 MPH?
Use:
Time = Distance ÷ Speed
Time = 3 ÷ 3
Time = 1 hour
This is a simplified estimate assuming an average walking speed of exactly 3 mph for the entire route.
For actual walking routes, see Walking Route Distance Calculator.
How Does This Relate to Driving Distance?
The distance-speed-time formula works with a distance value, but that distance must first come from somewhere.
For a real road trip:
Road-network routing → Driving Distance
then:
Distance + Speed → Travel Time
Your Driving Distance Calculator already returns both route mileage and a routing-based estimated duration.
This page explains the underlying mathematical relationship between those quantities.
Distance-Speed-Time vs Geographic Distance Formula
These formulas answer completely different questions.
Distance-Speed-Time
Uses movement information:
Distance = Speed × Time
Geographic Distance
Uses positions or coordinates.
For example, the Distance Calculator calculates great-circle distance between two latitude/longitude points.
So:
speed/time formula
asks how far something travels.
coordinate distance formula
asks how far apart two positions are.
Distance-Speed-Time vs Euclidean Distance Formula
Euclidean distance uses:
Distance = √[(x₂ − x₁)² + (y₂ − y₁)²]
This measures separation between Cartesian points.
Distance-speed-time uses:
Distance = Speed × Time
This measures traveled distance from a rate and duration.
Both produce a quantity called distance, but the input information and mathematical model are different.
For the broader mathematical formulas, see the Distance Formula hub.
Common Distance Speed Time Mistakes
1. Mixing Minutes and Hours
If speed is in mph, convert minutes to hours.
2. Mixing Miles and Kilometers
Do not combine:
miles
with:
km/h
without converting one of them.
3. Confusing Speed With Distance
Speed must contain a time unit such as:
mph
or:
km/h
4. Using the Speed Limit as Average Speed
A road's maximum speed does not automatically equal the trip's average speed.
5. Forgetting to Rearrange the Formula
Use:
Distance = Speed × Time
Speed = Distance ÷ Time
Time = Distance ÷ Speed
6. Averaging Speeds Incorrectly
Do not automatically calculate:
(Speed 1 + Speed 2) ÷ 2
unless the relevant time weighting makes that valid.
7. Dividing by Zero
Time and speed denominators cannot be zero when solving for speed or time from nonzero values.
Distance Speed Time Quick Reference
| Find | Formula |
|---|---|
| Distance | Distance = Speed × Time |
| Speed | Speed = Distance ÷ Time |
| Time | Time = Distance ÷ Speed |
Common U.S. units
Distance: miles
Speed: miles per hour
Time: hours
Common metric units
Distance: kilometers
Speed: kilometers per hour
Time: hours
or:
Distance: meters
Speed: meters per second
Time: seconds
Which Formula Should You Use?
Use:
Distance = Speed × Time
when you know speed and time.
Speed = Distance ÷ Time
when you know distance and time.
Time = Distance ÷ Speed
when you know distance and speed.
The most important practical rule is to make the units compatible before performing the calculation.
Frequently Asked Questions
What is the distance speed time formula?
The fundamental formula is:
Distance = Speed × Time
It can be rearranged as:
Speed = Distance ÷ Time
and:
Time = Distance ÷ Speed
What is the speed formula?
Use:
Speed = Distance ÷ Time
For example, 180 miles in 3 hours gives an average speed of 60 mph.
What is the travel time formula?
Use:
Time = Distance ÷ Speed
For example, 240 miles at 60 mph takes 4 hours mathematically.
How do you calculate distance?
Multiply speed by time:
Distance = Speed × Time
Can I use minutes with miles per hour?
Yes, but convert minutes into hours first.
Is speed the same as velocity?
No. Speed describes magnitude only, while velocity also includes direction.
What is average speed?
Average speed is:
Total Distance ÷ Total Time
Is average speed the average of two speeds?
Not necessarily. It depends on how much time or distance is traveled at each speed.
Can speed be negative?
Ordinary speed is nonnegative. Velocity can be signed when direction is represented mathematically.
Can distance be negative?
Ordinary traveled distance cannot be negative.
How does this relate to driving distance?
A driving calculator finds the road-route distance. The distance-speed-time relationship can then be used to understand how distance, average speed, and travel duration relate.