The Orbitrap mass analyzer can provide high mass accuracy and throughput, which has significantly improved proteome research and made this type of instrumentation one of the most frequently applied in proteomics. Efficient use of Orbitrap mass spectrometers require training. Students in the field of proteomics would certainly benefit from a deeper understanding of the Orbitrap technology in order to comprehend mass spectral interpretation, troubleshooting, and judgment of experimental settings. Unfortunately, the cost of high-end mass spectrometers limits the implementation of this type of equipment in educational laboratories. Guided by these concerns we developed an eLearning web-application called HUMOS aimed to help teaching Orbitrap mass spectrometry. The application is running on a web server and can be accessed by any modern web browser. HUMOS models a mass spectrum of a peptide mixture allowing to investigate the influence of mass spectral acquisition parameters on it. By changing the parameters and observing the differences students are able to learn more about mass spectral resolution, duty cycle, the throughput of the analysis, ion accumulation, spectral dynamic range, and get familiar with advanced spectral acquisition methods, such as BoxCar. HUMOS is an open-source software published under Apache license; the live demo is available at http://humos.bmb.sdu.dk.