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Encoder Resolution Calculator

Work out encoder resolution instantly with clear inputs, formula shown and shareable results.

About Encoder Resolution Calculator

Quadrature decoding multiplies an encoder's line count by four, since both channels give a transition every quarter cycle. Multiplying again by the gear ratio and dividing by travel per revolution gives counts per millimetre — the figure that sets closed-loop resolution.

Formula

Encoder resolution

counts = PPR x decoding x gear ratio; resolution = travel per rev / counts

Worked example

With the default values below, Encoder Resolution Calculator returns Counts per output revolution of 50,000. Change any input above and every figure here is recalculated in your browser.

Inputs used

Encoder pulses per revolution
2,500 PPR
Decodingone of x1 decoding, x2 decoding, x4 quadrature decoding
x4 quadrature decoding
Gear ratio between encoder and output
5 :1
Output travel per revolution
60 mm

Results

Counts per output revolution
50,000 counts
Linear resolution
1.20 µm
Angular resolution
25.92 arcsec
Counts per millimetre
833.33 counts/mm

Step by step

  1. 1Values used
  2. 2Encoder resolution
  3. 3Counts per output revolution= 50,000 counts
  4. 4Linear resolution= 1.20 µm
  5. 5Angular resolution= 25.92 arcsec
  6. 6Counts per millimetre= 833.33 counts/mm

Assumptions and limits

  • The result is derived only from the 4 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

Is x4 decoding free accuracy?

It is free resolution, not accuracy. Quadrature edges are only as accurate as the disc pattern and the interpolation electronics.

Where should the encoder be mounted?

On the load side if accuracy matters, since a motor-mounted encoder cannot see backlash, belt stretch or compliance in the transmission.

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