Intensity modulated neutron radiotherapy (IMNRT) is currently being investigated as a mechanism to improve dose conformality in neutron radiotherapy, thereby minimizing normal tissue toxicity. This study investigates the applicability of two different dose calculation algorithms for IMNRT, a commercial system which utilizes a finite size pencil beam (FSPB) model, and an in-house planning system which uses a differential scatter air ratio (DSAR) method. Calculated dose distributions were compared with measured profiles for validation purposes. The beam-profiles matched to within ±3% in the central region of the field. The 80-20% penumbra width as measured using an ionization chamber varied as 0.6 cm and 1.0 cm for 3 × 3 and 10 × 10 cm2 profile at a depth of 2.5 cm. The FSPB model fitted the data to a penumbra width of O.1 cm for both 3 × 3 and 10 × 10 cm2 profiles. These results indicate that the commercial system needs further investigation. However, the in-house planning system has been validated for small irregular fields for IMNRT to an accuracy of ±5%. Absolute dose measurements agreed with the calculated doses to within ±3%.