We present a new software tool, Ambit-HNMR, for automatic calculation of 1H-NMR chemical shifts of organic compounds. Ambit-HNMR is an open-source software, written in Java, part of the chemoinformatics platform Ambit. Ambit-HNMR software uses a CDK based molecule presentation as connection table where H atoms are treated implicitly. The chemical shifts for each H atom are calculated by means of so called H-atom environments which describe different types of resonance protons. Each H-atom environment consists...