Work out encoder resolution instantly with clear inputs, formula shown and shareable results.
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.
Encoder resolution
counts = PPR x decoding x gear ratio; resolution = travel per rev / counts
It is free resolution, not accuracy. Quadrature edges are only as accurate as the disc pattern and the interpolation electronics.
On the load side if accuracy matters, since a motor-mounted encoder cannot see backlash, belt stretch or compliance in the transmission.