Differential Drive Speed Calculator

Work out differential drive speed instantly with clear inputs, formula shown and shareable results.

About Differential Drive Speed Calculator

Differential drive kinematics: linear speed is the average of the wheel speeds and angular speed is their difference divided by the track width. Turn radius is v/omega, which goes to zero when the wheels turn in opposite directions at equal speed — a spin on the spot.

Formula

Differential drive

v = (vL + vR)/2; omega = (vR - vL)/track; R = v / omega

Worked example

With the default values below, Differential Drive Speed Calculator returns Robot linear speed of 1.00. Change any input above and every figure here is recalculated in your browser.

Inputs used

Left wheel speed: 1.2 m/s
Right wheel speed: 0.8 m/s
Wheel track width: 450 mm

Results

Robot linear speed: 1.00 m/s
Angular speed: -0.89 rad/s
Turn radius: -1.13 m
Rotation rate: -50.93 °/s

Step by step

1Values used
2Differential drive
3Robot linear speed= 1.00 m/s
4Angular speed= -0.89 rad/s
5Turn radius= -1.13 m
6Rotation rate= -50.93 °/s

Assumptions and limits

The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

What happens when both wheels are equal?

Angular speed is zero and the radius is infinite: the robot drives straight. The calculator reports zero radius rather than infinity in that case.

Why does a narrow track spin faster?

Angular speed is the wheel speed difference divided by the track, so a narrower robot rotates faster for the same difference — and is also twitchier to control.