Abstract Chiral helimagnets have attracted significant attention due to their unique spin textures, dynamics, and potential in next‐generation spintronic technologies. However, calculating helimagnetic properties accurately remains a challenge owing to the complexity of the helical spin configurations and the long‐range periodicity. Here, a universal approach is reported for modeling and predicting helimagnetic spin structures by extracting the total energy as a function of the spin rotation angle between successive layers of helimagnets using first‐principles calculations. Applying this approach to Cr‐intercalated transition metal dichalcogenides, Cr 1/3 MX 2 (where M = Nb, Ta; X = S, Se), their monoaxial magnetic helix parameters are successfully predicted, including helix wavevector, helix period, and critical magnetic field. This approach opens new avenues for the discovery of helimagnetic materials.