# Speed vs. Velocity — What's the Difference?

By Tayyaba Rehman — Updated on October 13, 2023
Speed is a scalar measuring how fast something moves, while Velocity is a vector measuring speed in a specific direction.

## Key Differences

Speed and Velocity are fundamental concepts in physics. Speed is a scalar quantity, which means it only has magnitude and doesn't have a direction. It tells us how fast an object is moving without regard to its direction. On the other hand, Velocity is a vector quantity, meaning it has both magnitude and direction. This distinction makes Velocity more descriptive as it indicates not just the rate of movement but also where the object is headed.
When we say a car has a Speed of 50 mph, we're merely referring to its rate of motion. But when we say its Velocity is 50 mph to the north, we provide additional information about its direction.
While Speed can never be negative, Velocity can be, indicating a change in direction.
For instance, a negative Velocity can show that an object is moving in the opposite direction than what was initially considered positive.

## Comparison Chart

Scalar
Vector

### Magnitude

Only has magnitude
Has magnitude and direction

### Direction

Does not consider direction
Always considers direction

### Negative Value

Can't be negative
Can be negative (indicating reverse direction)

### Change

Changes only in magnitude
Changes in magnitude or direction or both

## Compare with Definitions

#### Speed

The rate at which an object moves.
The car's Speed was consistent at 60 mph.

#### Velocity

The rate and direction of an object's movement.
The Velocity of the river's current was 5 m/s to the east.

#### Speed

In everyday use and in kinematics, the speed (commonly referred to as v) of an object is the magnitude of the rate of change of its position with time or the magnitude of the change of its position per unit of time; it is thus a scalar quantity. The average speed of an object in an interval of time is the distance travelled by the object divided by the duration of the interval; the instantaneous speed is the limit of the average speed as the duration of the time interval approaches zero.

#### Velocity

A vector quantity showing both speed and direction.
The ball's Velocity indicated it was moving quickly westward.

#### Speed

The rate at which someone or something moves or operates or is able to move or operate
We turned on to the runway and began to gather speed
The car has a top speed of 147 mph
An engine running at full speed

#### Velocity

Can have positive or negative values based on reference direction.
A negative Velocity indicates movement in the opposite direction.

#### Speed

Each of the possible gear ratios of a bicycle.

#### Velocity

The displacement of an object per unit time.
With a constant Velocity, the object moved steadily north.

#### Speed

The light-gathering power or f-number of a camera lens.

#### Velocity

A measure considering both the speed and direction of movement.
While their Speeds were the same, their Velocities differed due to opposing directions.

#### Speed

An amphetamine drug, especially methamphetamine.

#### Velocity

The velocity of an object is the rate of change of its position with respect to a frame of reference, and is a function of time. Velocity is equivalent to a specification of an object's speed and direction of motion (e.g.

#### Speed

Success; prosperity
Wish me good speed

#### Velocity

The speed of something in a given direction
The velocities of the emitted particles

#### Speed

Move quickly
I got into the car and home we sped

#### Velocity

Rapidity or speed of motion; swiftness.

#### Speed

Make prosperous or successful
May God speed you

#### Velocity

(Physics) A vector quantity whose magnitude is a body's speed and whose direction is the body's direction of motion.

#### Speed

Take or be under the influence of an amphetamine drug
More kids than ever are speeding, tripping, and getting stoned

#### Velocity

The rate at which something acts or occurs
The velocity of metabolism of glucose in muscle cells.

#### Speed

Distance traveled divided by the time of travel.

#### Velocity

The rate at which money changes hands in an economy.

#### Speed

The limit of this quotient as the time of travel becomes vanishingly small; the first derivative of distance with respect to time.

#### Velocity

(physics) A vector quantity that denotes the rate of change of position with respect to time, combining speed with a directional component.

#### Speed

The magnitude of a velocity.

#### Velocity

Rapidity of motion.
The train was travelling at a slower velocity than usual.

#### Speed

Swiftness of action
He wrote the first chapter with great speed.

#### Velocity

The rate of occurrence.

#### Speed

The act of moving rapidly
Finished the race in a burst of speed.

#### Velocity

(economics) The number of times that an average unit of currency is spent during a specific period of time.

#### Speed

The state of being in rapid motion; rapidity
The river's speed made a rescue difficult.

#### Velocity

Quickness of motion; swiftness; speed; celerity; rapidity; as, the velocity of wind; the velocity of a planet or comet in its orbit or course; the velocity of a cannon ball; the velocity of light.

#### Speed

A transmission gear or set of gears in a motor vehicle
What speed is the car in now?.

#### Velocity

Rate of motion; the relation of motion to time, measured by the number of units of space passed over by a moving body or point in a unit of time, usually the number of feet passed over in a second. See the Note under Speed.

#### Speed

A numerical expression of the sensitivity of a photographic film, plate, or paper to light.

#### Velocity

Distance travelled per unit time

#### Speed

The capacity of a lens to accumulate light at an appropriate aperture.

#### Speed

The length of time required or permitted for a camera shutter to open and admit light.

#### Speed

(Slang) A stimulant drug, especially amphetamine or methamphetamine.

#### Speed

(Slang) One that suits or appeals to a person's inclinations, skills, or character
Living in a large city is not my speed.

#### Speed

(Archaic) Prosperity; luck.

#### Speed

To go, move, or proceed quickly
Sped to the rescue.

#### Speed

To drive at a speed exceeding a legal limit
Was speeding on the freeway.

#### Speed

To pass quickly
The days sped by. The months have sped along.

#### Speed

To move, work, or happen at a faster rate; accelerate
His pulse speeded up.

#### Speed

(Slang) To be under the influence of a stimulant drug.

#### Speed

To prove successful; prosper.

#### Speed

To get along in a specified manner; fare.

#### Speed

To cause to move or proceed quickly; hasten
No wind to speed the boat.

#### Speed

To increase the speed or rate of; accelerate. Often used with up
Speed up a car.
Sped up production.

#### Speed

To further, promote, or expedite (a legal action, for example).

#### Speed

(Archaic) To help to succeed or prosper; aid.

#### Speed

The state of moving quickly or the capacity for rapid motion.
How does Usain Bolt run at that speed?

#### Speed

The rate of motion or action, specifically the magnitude of the velocity; the rate distance is traversed in a given time.
Speed limits provide information to the drivers about the safe speed to travel in average conditions.

#### Speed

(photography) The sensitivity to light of film, plates or sensor.

#### Speed

(photography) The duration of exposure, the time during which a camera shutter is open (shutter speed).

#### Speed

(photography) The largest size of the lens opening at which a lens can be used.

#### Speed

(photography) The ratio of the focal length to the diameter of a photographic objective.

#### Speed

Amphetamine or any amphetamine-based drug (especially methamphetamine) used as a stimulant, especially illegally.

#### Speed

(archaic) Luck, success, prosperity.

#### Speed

(slang) Personal preference.
We could go to the shore next week, or somewhere else if that's not your speed.

#### Speed

A third-order measure of derivative price sensitivity, expressed as the rate of change of gamma with respect to changes in the underlying asset price.

#### Speed

(film) Called by the soundman when the recording equipment has reached running speed and is ready to go.

#### Speed

To succeed; to prosper, be lucky.

#### Speed

To help someone, to give them fortune; to aid or favour.
God speed, until we meet again.

#### Speed

(intransitive) To go fast.
The Ferrari was speeding along the road.

#### Speed

(intransitive) To exceed the speed limit.
Why do you speed when the road is so icy?

#### Speed

(transitive) To increase the rate at which something occurs.

#### Speed

To be under the influence of stimulant drugs, especially amphetamines.

#### Speed

(obsolete) To be expedient.

#### Speed

(archaic) To hurry to destruction; to put an end to; to ruin.

#### Speed

(archaic) To wish success or good fortune to, in any undertaking, especially in setting out upon a journey.

#### Speed

To cause to make haste; to dispatch with celerity; to drive at full speed; hence, to hasten; to hurry.

#### Speed

To hasten to a conclusion; to expedite.

#### Speed

Prosperity in an undertaking; favorable issue; success.
O Lord God of my master Abraham, I pray thee, send me good speed this day.

#### Speed

The act or state of moving swiftly; swiftness; velocity; rapidly; rate of motion; dispatch; as, the speed a horse or a vessel.
Speed, to describe whose swiftness number fails.

#### Speed

One who, or that which, causes or promotes speed or success.

#### Speed

To go; to fare.
To warn him now he is too farre sped.

#### Speed

To experience in going; to have any condition, good or ill; to fare.
Ships heretofore in seas like fishes sped; The mightiest still upon the smallest fed.

#### Speed

To fare well; to have success; to prosper.
Save London, and send true lawyers their meed!For whoso wants money with them shall not speed!
I told ye then he should prevail, and speedOn his bad errand.

#### Speed

To make haste; to move with celerity.
I have speeded hither with the very extremest inch of possibility.

To be expedient.

#### Speed

To cause to be successful, or to prosper; hence, to aid; to favor.
With rising gales that speed their happy flight.

#### Speed

To cause to make haste; to dispatch with celerity; to drive at full speed; hence, to hasten; to hurry.
He sped him thence home to his habitation.

#### Speed

To hasten to a conclusion; to expedite.
Judicial acts . . . are sped in open court at the instance of one or both of the parties.

#### Speed

To hurry to destruction; to put an end to; to ruin; to undo.
A dire dilemma! either way I 'm sped.If foes, they write, if friends, they read, me dead.

#### Speed

To wish success or god fortune to, in any undertaking, especially in setting out upon a journey.
Welcome the coming, speed the parting guest.

#### Speed

Distance travelled per unit time

#### Speed

A rate (usually rapid) at which something happens;
The project advanced with gratifying speed

#### Speed

Changing location rapidly

#### Speed

The ratio of the focal length to the diameter of a (camera) lens system

#### Speed

A central nervous system stimulant that increases energy and decreases appetite; used to treat narcolepsy and some forms of depression

#### Speed

Step on it;
He rushed down the hall to receive his guests
The cars raced down the street

#### Speed

Move faster;
The car accelerated

#### Speed

Travel at an excessive or illegal velocity;
I got a ticket for speeding

#### Speed

Move very fast;
The runner zipped past us at breakneck speed

#### Speed

Cause to move faster;
He accelerated the car

#### Speed

How fast something moves, irrespective of direction.
The Speed of the wind made it difficult to walk.

#### Speed

A measure of distance covered per unit time.
The Speed of light is approximately 186,282 miles per second.

#### Speed

A scalar quantity showing only magnitude.
Speed is concerned with how fast, not where.

#### Speed

A measure not considering the direction of movement.
Speedometers in cars display Speed, not Velocity.

## Common Curiosities

#### Is Speed always positive?

Yes, Speed, being a scalar, is always positive or zero.

#### Can Velocity be zero?

Yes, Velocity is zero when there's no displacement, even if the object moved.

#### Why is Velocity considered a vector?

Velocity is a vector because it has both magnitude (speed) and direction.

#### Can Speed be zero?

Yes, Speed is zero when an object is stationary.

#### What's the relation between Speed and Velocity?

Speed is the magnitude of Velocity.

#### Can two objects have the same Speed but different Velocities?

Yes, if they move at the same rate but in different directions, their Velocities differ.

#### Can average Speed and average Velocity be different?

Yes, especially if an object returns to its starting point; its displacement (and thus Velocity) might be zero.

#### How do we find average Speed?

Average Speed is total distance divided by total time.

#### How do we find average Velocity?

Average Velocity is total displacement divided by total time.

#### Does a turning car have changing Velocity?

Yes, because even if its Speed remains constant, its direction changes.

#### What does negative Velocity mean?

Negative Velocity means movement opposite to the reference positive direction.

#### Is it accurate to use Speed and Velocity interchangeably?

No, because Speed is scalar, and Velocity is vector; they convey different information.

#### In circular motion, is Speed constant but Velocity changing?

Yes, because while the magnitude (Speed) might be constant, the direction changes continuously.

#### Do Speed bumps affect Speed or Velocity?

They affect both since they reduce an object's rate and can change its direction.

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