How do you calculate velocity?

Divide the distance travelled by the time taken: v = d ÷ t. Usain Bolt's world record is 100 metres in 9.58 seconds, so his average velocity was 100 ÷ 9.58 = 10.44 m/s, which is 37.58 km/h or 23.35 mph. Convert both quantities to consistent units before dividing — mixing kilometres with seconds, or metres with hours, is the single commonest source of a wrong answer.

What is the difference between speed and velocity?

Speed is a scalar — a size with no direction, calculated from the total distance you covered. Velocity is a vector — a size with a direction, calculated from your displacement, which is the straight line from start to finish. Walk 3 km east then 4 km north in one hour and your speed is 7 km/h, but your displacement is only 5 km, so your velocity is 5 km/h north-east. Travel in a single straight line and the two are equal, which is why they are so often used interchangeably.

Can velocity be zero when you are moving quickly?

Yes, and a running track is the clearest example. Complete a full lap and you finish exactly where you started, so your displacement is zero. Since average velocity is displacement divided by time, your average velocity for that lap is exactly zero — no matter how fast you ran. Your average speed, calculated from the 400 metres you actually covered, is unaffected. Try the Full lap route in the simulation above and watch the velocity readout fall to zero as the runner closes the loop.

What is the difference between average and instantaneous velocity?

Average velocity covers a whole journey: total displacement divided by total time. Instantaneous velocity is your velocity at one specific moment — what a speedometer shows. A car might average 50 km/h across a city trip while never actually holding 50 km/h, sitting at 0 in traffic and 70 on a clear road. This calculator finds the average. Instantaneous velocity needs calculus, or the constant-acceleration formulas listed above.

How do I convert between m/s, km/h and mph?

Multiply metres per second by 3.6 to get km/h, and by 2.2369 to get mph. Going the other way, divide km/h by 3.6 or multiply mph by exactly 0.44704. So 10 m/s is 36 km/h or 22.37 mph, and 60 mph is exactly 26.8224 m/s. These factors come from the exact definitions — one mile is exactly 1,609.344 metres and one hour is 3,600 seconds — so they are not approximations.

What does the slope of a distance-time graph mean?

The slope is the velocity. Rise divided by run is distance divided by time, which is exactly the definition of velocity, so a steeper line means faster motion. A perfectly straight line means the velocity never changed. A curve that steepens means speeding up, a curve that flattens means slowing down, and a horizontal section means the object is stationary. Reading motion straight off the gradient is one of the most useful habits in physics.

What is a knot, and why do ships and aircraft use it?

A knot is one nautical mile per hour, and a nautical mile is exactly 1,852 metres — defined as one minute of latitude along a meridian. That definition is what makes it useful: navigating by latitude and longitude, distances in nautical miles map directly onto the chart, so speed in knots translates straight into position. One knot is about 0.514 m/s, or 1.852 km/h.

How fast can humans and animals actually move?

A comfortable walk is about 1.4 m/s and a recreational cyclist manages around 5.6 m/s. Usain Bolt averaged 10.44 m/s over his record 100 metres, peaking near 12.4 m/s. A cheetah in full sprint reaches roughly 29 m/s, about 104 km/h, but only holds it for a few hundred metres. For scale, sound travels at about 340 m/s in air and the International Space Station orbits at roughly 7,660 m/s.

Can velocity be negative?

Yes, and the negative sign is information rather than an error. Because velocity is a vector, its sign records direction relative to whichever way you chose to call positive. An object moving at −5 m/s is travelling at 5 m/s in the negative direction. Speed, having no direction, is never negative — it is the magnitude of the velocity. This is why a ball thrown upward has positive velocity on the way up and negative on the way down, while its speed is positive throughout.

Velocity Calculator (v = d / t)

Calculate velocity, distance or time from v = d ÷ t — the first equation of motion and the one every other kinematics formula builds on. Enter any two of the three and this calculator returns the third, converts it into metres per second, km/h, mph and knots, and shows you how that speed compares wi...

v = d / t

SOLVE FOR

DISTANCE

TIME

EVERYDAY JOURNEYS

AVERAGE VELOCITY

10.438 m/s

KM/H

37.58

MPH

23.35

KNOTS

20.29

Distance travelled ÷ time taken. For travel in one straight line this is also the average speed.

Distance

100.00 m

Time

9.580 s

Velocity

10.438 m/s

Feet per second

34.25 ft/s

Distance in 1 h

37.58 km

Time for 1 km

95.8 s

STEPS

Convert to SI: distance = 100.0000 m, time = 9.5800 s

Divide distance by time: v = d ÷ t

v = 100.0000 ÷ 9.5800 = 10.4384 m/s

VELOCITY vs SPEED

ROUTE SHAPE

DISTANCE

0.0 m

DISPLACEMENT

0.0 m

AVG SPEED

10.44 m/s

AVG VELOCITY

0.00 m/s

Speed is a number; velocity is a number with a direction. Travelling in one straight line, the displacement equals the distance covered, so average velocity and average speed come out the same. That is the case this calculator assumes.

DISTANCE–TIME GRAPH — SLOPE IS THE VELOCITY

Velocity is the slope of this line: rise ÷ run = 100.0 m ÷ 9.58 s = 10.438 m/s. A straight line means constant velocity; a curve would mean it was changing.

HOW FAST IS THAT?

AT THIS SPEED

100 metres takes

9.58 s

One mile takes

2.57 min

In one minute

626.3 m

In one hour

37.58 km

Live simulation · updates as you type

Created with❤️byeaglecalculator.com

HOW TO USE

1
Choose what to find with the SOLVE FOR buttons: Velocity, Distance or Time. The fields change to ask for whichever two quantities the calculation needs.
2
Enter your values and pick the units beside each field. Distance in metres, kilometres, miles, feet, yards or nautical miles; time in seconds, minutes, hours, milliseconds or days; velocity in m/s, km/h, mph, ft/s or knots. Mixing units is safe — everything converts to SI first.
3
Read the answer in the black box, with three alternative units below it. The key-facts grid adds practical figures such as how far you would travel in an hour and how long a kilometre would take at that pace.
4
Use the ROUTE SHAPE buttons on the right to see the difference between speed and velocity. All three routes cover the same distance in the same time, but only the straight one gives a velocity equal to the speed.

THE FORMULAS

Average velocityv = Δd / Δt

Solve for distanced = v × t

Solve for timet = d / v

Average speedtotal distance / time

Average velocitydisplacement / time

Final velocityv = v₀ + a t

Without timev² = v₀² + 2 a d

One metre per second= 3.6 km/h = 2.237 mph

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Last updated: July 29, 2026 · Formula verified · Eagle-eyed accuracy for every calculation.