CO LF in different redshift bins, from z = 0 to z = 6, as is indicated at the top right of each panel. The measurements from ALMACAL-22 are shown in purple, including the uncertainty of each bin given by the extension of the boxes. We derived the CO LF based on the CO(1–0) luminosity, calculated as is explained in Sect. 4.2. For comparison, we include observational constraints found by previous surveys at similar redshift ranges: ASPECS (Decarli et al. 2019, 2020), PHIBSS2 (Lenkić et al. 2023), COLDz (Riechers et al. 2019), HDFN (Boogaard et al. 2023). In some cases, the estimates from these surveys were derived from different CO transitions, here we converted the luminosities $L_{\mathrm{CO}(1-0)}\prime$ consistently to our methodology. The CO LF derived from the ALMACAL survey aligns well with findings from other surveys, while probing a wider redshift range.