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Wheel Travel Calculator

How far does one wheel turn take you, and how many turns to reach a target distance?

Inputs

in

VEX V5 sizes: 2" omni, 2.75", 3.25", 4", Mecanum, 4", Flex wheel, 4", Flex wheel, 3", Flex wheel, 2". Any value is accepted.

in

One foam tile is 24 inches. The full field is 144.

Results

Distance per wheel turn

—in

Same figure in millimeters

—mm

Turns to cover your distance

—

Which is this much wheel rotation

—°

Turns per tile

—

24 inches.

Turns across the field

—

144 inches.

Your distance in tiles

—

When you would use this

  1. Our autonomous overshoots by a consistent amount.

    Work out the real distance per turn from your actual wheel, not the advertised travel figure. VEX rounds that to the nearest 10 mm, and over a field length the rounding alone adds up.

  2. We want to drive exactly one tile.

    Enter the tile distance and read the turns needed. Feed that to your code as wheel turns, then multiply by your gear ratio to get motor turns.

  3. We changed from 3.25 to 4 inch wheels and everything is off.

    Run it for both. The ratio between the two distances per turn is exactly the factor every distance in your code has to change by.

How this is calculated

A wheel rolling without slipping travels exactly its own circumference in one turn. That single fact is behind most simple autonomous routines.

distance per turn = π × diameter turns needed = distance ÷ distance per turn degrees = turns × 360

Note that this is wheel rotation, not motor rotation. If there is gearing between the motor and the wheel, the motor turns a different amount. Converting between the two is what theOdometry Ticks per Inch calculator does.

Why your robot will undershoot

Driving a measured number of turns is reliable enough to build an autonomous around, but it drifts, for reasons no formula fixes:

  • Wheels slip. Every start and stop loses a little distance, and omni wheels lose more than traction wheels.
  • Wheels compress. A loaded wheel has a slightly smaller effective radius than the one printed on the side.
  • Wheels wear. A well-used wheel is measurably smaller than a new one.

The practical fix is to drive a known distance, measure where you actually stopped, and scale your numbers by the error. Do that once per wheel set and your autonomous will beat anything derived purely from the maths.

Sources & assumptions

Wheel diameters listed are VEX published sizes. Circumference is computed as π × diameter. VEX also advertises a "travel" figure per wheel of 220, 260 and 320 mm, which is the same measurement rounded to the nearest 10 mm; this page shows the exact value instead, and flags the difference when you enter a standard size.

Assumes rolling without slip on a flat surface, and a wheel diameter that does not change under load. Neither is exactly true on a real robot.

Save this run, and compare

Keeps what is on screen so you can change something and see both sides of the change. Saved in this browser only, never uploaded.

Save this as evidence

Collects what you entered, what came out, how it was worked out, and anything the tool flagged, with a timestamp and a version so someone else can reproduce it.

This is evidence, not a notebook entry. It deliberately does not write your problem statement, your reasoning, or your conclusion, because under RECF rules an Engineering Notebook has to be the students' own work and no tool may generate or organise its content. Take the numbers, decide what matters, and write it yourself.