  We present an analysis of polarimetric observations of standard stars
performed over the period of more than three years with the RINGO3 polarimeter
mounted on the Liverpool Telescope. The main objective was to determine the
instrumental polarisation of the RINGO3 polarimeter in three spectral energy
ranges: blue (350--640~nm), green (650--760~nm) and red (770--1000~nm). The
observations were conducted between 2012 and 2016. The total time span of 1126
days was split into five epochs due to the hardware changes to the observing
system. Our results should be applied to calibrate all polarimetric
observations performed with the RINGO3 polarimeter.
