Machine learning estimation of reaction energy barriers

•Reaction energy barriers were predicted with machine learning.•The model was trained and tested on 11,730 reactions involving H, C, N and O.•The model is simple and could be generalized to elements other than H, C, N, O.•The model can help screen hypothetical reactions in interstellar space.•For barriers smaller than 40 kcal/mol the mean absolute error is 4.1 kcal/mol.