In this paper feedback allocation of interference channels using multi-cell coordinated beamforming is studied. By fixing the total feedback budget as constant, the proposed interference grading threshold scheme adaptively allocating the feedback bits between inter-user interference and inter-cell interference. The individual feedback bits of inter-user and inter-cell interference are calculated by employing interference grading. A new iterative algorithm is proposed to find the total residual feedback bits. The proposed feedback allocation in interfering broadcast and time varying channels are numerically evaluated and it is found that the proposed method performs comparatively better than other counterparts.