Role of hyperfine interaction in Landé g-factors of 3P0o clock states

•In the weak-magnetic-field approximation, we calculated the hyperfine-induced Landé g-factors of the 3P0o clock states in 27Al+ and 87Sr by using the multi-configuration Dirac–Hartree–Fock method. The present results, δghfs(1)(3P0o)=−1.183(6)×10−3 for 27Al+ and δghfs(1)(3P0o)=7.78(30)×10−5 for 87Sr, agree with experimental values very well.•We also estimated the contributions from perturbing states to the g-factors concerned so as to truncate the summation over the perturbing states without loss of accuracy.•The computational uncertainties were systematically analyzed.