AGN surface density (deg⁻²) versus survey area (deg²) for EWS and EDS compared with wide field and medium area surveys in different wavebands (according to the legend). Unfilled downwards triangles show the surface density of AGN detected in at least one Euclid band (at 5 σ), while filled upwards triangles represent the surface density of AGN selected by using a simple colour criterion with Euclid and LSST colours, in both EWS and EDS.