Proximity effect correction for reticle making by the dose correction method is discussed. A new algorithm for calculating the optimum dose is proposed, which is based on the dose formula method and the representative figure method. Its main feature is that dose evaluation points are fixed at individual small regions whose size is sufficiently small compared with the backscattering range. The calculation speed of the computer is evaluated which is sufficient to suppress the correction time to less than the writing time. The required calculation speed is 500 MIPS×4 CPU at most for a minimum feature size greater than 0.2 μm on the reticle. This result suggests that the real‐time proximity effect correction is possible for making reticles. Furthermore, when the algorithm is applied to x‐ray mask fabrication and direct writing process, the calculation time can be suppressed to less than the writing time.