Velocity Calculator

Assess how fast an object moves

Calculate velocity using distance covered, acceleration, or a weighted average from multiple velocities.

CreatorFrank Zhao

How would you like to calculate velocity?

Distance covered

Distance

More info

Time

More info

sec

Velocity

More info

m/s

1Basic Velocity

v = \frac{d}{t}

2Acceleration

v_f = v_i + a\,t

3Weighted Average Velocity

\bar{v} = \frac{\sum_{i=1}^{N} v_i\,t_i}{\sum_{i=1}^{N} t_i}

ddistance

ttime

vvelocity

v_iinitial velocity

v_ffinal velocity

aacceleration

📚

This Velocity Calculator is a practical tool for turning the classic motion equations into instant answers. You can compute velocity from distance and time, find velocity change under constant acceleration, or calculate a weighted average velocity from up to ten segments.

→What is velocity? – velocity definition
→The average velocity formula and velocity units
→How to calculate velocity – speed vs. velocity
→Terminal velocity, escape velocity and relativistic velocity
→FAQs

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What is velocity? – velocity definition

In everyday language, people often say “speed” and “velocity” as if they’re the same thing. In physics, velocity is more specific: it describes how quickly your position changes and the direction you’re moving in.

Core idea (1D motion)

v = \frac{\Delta x}{\Delta t}

Here $\Delta x$ is the change in position (displacement along your chosen axis), and $\Delta t$ is the time interval.

Quick intuition: if you move 10 m east in 2 s, your velocity is 5 m/s east. If you go 10 m east and then 10 m west, your total distance is 20 m, but your displacement is 0 — so your average velocity can be close to 0.

This calculator focuses on linear velocity (straight-line motion). If you’re dealing with 2D vectors (like wind + aircraft airspeed), you’ll likely want a vector tool such as our Resultant Velocity Calculator.

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The average velocity formula and velocity units

The calculator includes three “routes” to a velocity answer — each matches a common physics situation:

Constant velocity

v = \frac{d}{t}

Use when motion is steady, or when you want an average over a whole interval.

Constant acceleration

v_f = v_i + a\,t

Great for starts, braking, or any smooth speed change where $a$ is roughly constant.

Weighted average velocity

\bar{v} = \frac{\sum_{i=1}^{N} v_i\,t_i}{\sum_{i=1}^{N} t_i}

Best when your trip has segments with different velocities and different durations.

🧾

Units you’ll see most often:

SI: $\mathrm{m/s}$ (meters per second)
Everyday metric: $\mathrm{km/h}$
Imperial: $\mathrm{ft/s}$ and $\mathrm{mph}$

The calculator lets you choose units per field and converts behind the scenes.

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How to calculate velocity – speed vs. velocity

Introduction / Overview

Think of velocity as “speed with a sign and a direction.” Speed answers “how fast,” while velocity answers “how fast, and which way.” In this calculator, you can represent direction by using positive/negative values (for example, “east” as positive and “west” as negative).

How to use / Quick start guide

Choose a method at the top: Distance covered, Acceleration, or Average velocity.
Enter any two (or three) known values. The missing field turns into the computed result.
Pick units for each field (the calculator converts automatically).
If you clear a field, the calculator treats it as “the one to solve next” (useful for exploring multiple scenarios).

Step-by-step example 1: distance and time

Suppose an object travels 500 meters in 3 minutes. To compute the average velocity in $\mathrm{m/s}$ , you can convert time to seconds and divide:

3\ \mathrm{min}

=

3\times 60\ \mathrm{s}

=

180\ \mathrm{s}

v

=

\frac{500}{180}

\mathrm{m/s}

\approx

2.78\ \mathrm{m/s}

In the calculator, you can simply enter $500$ for distance, set the unit to meters, enter $3$ for time, set the unit to minutes, and it will handle the conversion.

Step-by-step example 2: acceleration over time

Let’s say a car starts from rest and accelerates at $a = 6.95\ \mathrm{m/s^2}$ for $t = 4\ \mathrm{s}$ . With $v_i = 0$ , the final velocity is:

v_f

=

v_i + a\,t

=

0 + 6.95\times 4

=

27.8\ \mathrm{m/s}

If you want that in $\mathrm{km/h}$ , multiply by $3.6$ :

27.8\ \mathrm{m/s}

\times

3.6

\approx

100\ \mathrm{km/h}

Real-world examples / use cases

Road trip segments

Use the average mode when your route has a city part and a highway part. Enter each segment’s $v_i$ and $t_i$ to get a time-weighted average.

Acceleration & braking estimates

If you know how quickly something speeds up or slows down, the acceleration mode can estimate the missing variable in $v_f = v_i + a\,t$ .

Conveyor or treadmill speed checks

Measure a belt distance and the time it takes a marker to travel, then compute $v = d/t$ .

Free-fall intuition

For gravity-driven motion, you may want to pair this with our Free Fall Calculator, which uses the same kinematics family.

Common scenarios / when to use

Use Distance covered when motion is steady, or you just need an average across an interval.
Use Acceleration when $a$ is approximately constant.
Use Average velocity when you can split a trip into segments with different velocities and times.
Not ideal when direction changes matter a lot in 2D/3D — for that, use vector tools (see resultant velocity).

Tips & best practices

Treat $d$ as displacement when you care about direction (positive/negative).
If the calculator shows a negative time, it’s a mathematical result — but it usually indicates your chosen sign convention or inputs represent an impossible physical situation.
In average mode, don’t mix “distance segments” and “time segments” — this calculator uses time weighting ( $t_i$ ).
For acceleration magnitude only, try our Magnitude of Acceleration Calculator.

Calculation method / formula explanation

All three modes are built on standard kinematics. The distance mode uses the simple ratio $v = d/t$ . The acceleration mode uses the constant-acceleration relation $v_f = v_i + a\,t$ . The average mode uses a weighted mean based on time:

\bar{v} = \frac{v_1 t_1 + v_2 t_2 + \cdots + v_N t_N}{t_1 + t_2 + \cdots + t_N}

Variables

$v$ , $v_i$ , $v_f$ : velocity (initial/final)
$a$ : acceleration
$t$ , $t_i$ : time (segment time)
$d$ : distance (or displacement, depending on your interpretation)

🌌

Terminal velocity, escape velocity and relativistic velocity

“Velocity” shows up in many specialized contexts. This calculator covers the everyday kinematics side, but it’s helpful to know a few famous velocity ideas.

Terminal velocity

The maximum steady speed reached by a falling object in a fluid when drag balances weight. If you’re exploring that, try our Terminal Velocity Calculator.

Escape velocity

The minimum speed needed to leave a planet’s gravitational influence without further propulsion. For Earth, it’s about $11.2\ \mathrm{km/s}$ .

Relativistic velocity

At extremely high speeds, classical formulas break down and special relativity takes over. A key rule is that no massive object can reach $c$ (the speed of light).

If you’re learning kinematics, a nice workflow is: compute a velocity here, then plug it into a scenario (free fall, terminal velocity, or vector addition) to build intuition.

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FAQs

Can velocity be negative?

Yes. If you choose a positive direction (for example, “east”), then motion in the opposite direction (“west”) has a negative velocity. In 1D kinematics, the sign of $v$ carries direction.

What is the difference between velocity and acceleration?

Velocity describes motion itself (how position changes with time), while acceleration describes how velocity changes with time. In formulas, velocity is often $v$ and acceleration is $a$ , with units $\mathrm{m/s}$ and $\mathrm{m/s^2}$ respectively.

How do I find the initial velocity?

If you know $v_f$ , $a$ , and $t$ , rearrange the constant-acceleration equation:

v_i = v_f - a\,t

How do I find the final velocity?

If you know $v_i$ , $a$ , and $t$ , use:

v_f = v_i + a\,t

How do you find instantaneous velocity?

Instantaneous velocity is the derivative of position with respect to time. If position is $x(t)$ , then:

v(t) = \frac{dx}{dt}

Limitations / disclaimers

The calculator assumes 1D kinematics (a single chosen direction). Real motion can be 2D/3D.
For the acceleration method, accuracy depends on how constant your acceleration really is.
This tool is for education and estimation; it’s not a substitute for professional engineering or safety analysis.

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