PurposeTo provide a validation of a three‐dimensional (3D) macroscopic model for superconductors comparing numerical to experimental AC losses of a BSCCO‐2223 tape subject to an orthogonal magnetic field and a transport current.Design/methodology/approachWe solve in 3D geometries the eddy current problem in presence of superconductors, represented by a power‐law characteristic rewritten into a variational form. An integral formulation of the magneto‐quasistatic Maxwell's equations is used. The solution of the problem is found by an unconstrained minimization of a suitable functional. The numerical results on AC losses computation are compared to experimental data.FindingsThe agreement between numerical and experimental data is good in a wide range of currents and magnetic fields.Research limitations/implicationsThe magnetic field is assumed to be orthogonal to the tape. Different incidence angles should be taken into account.Practical implicationsIt is possible to extend the range of validity of the engineering formulae for AC losses used in the work.Originality/valueThe paper provides a validation of a numerical code against experimental results: this is always challenging in the field of applied superconductivity.