Volume-weighted mean magnetic field strength in μG, measured for all gas within 0.5 R_500c of halos, as a function of halo mass. Color indicates three distinct redshifts considered, from z = 0 to z = 2. Circular (square) markers show halos from TNG300 (TNG-Cluster). We provide several qualitative, face-value comparisons with observational inferences from Faraday rotation measure analyses (Bonafede et al. 2010; Böhringer et al. 2016; Govoni et al. 2017; Di Gennaro et al. 2021). The magnetic field strength in the inner ICM has characteristic values of order ∼μG, increasing for larger halo masses, higher redshifts (at fixed mass), and smaller cluster-centric distances.