Quantum sensing is a rapidly evolving field with the outlook of surpassing classical limitations. The field encompasses techniques such as noise-reduced imaging, super-resolution microscopy, as well as imaging and spectroscopy in challenging spectral ranges. Spontaneous parametric down-conversion sources are often employed for the generation of the correlated biphoton states required for these detection schemes. In this work a general simulation method is demonstrated and used to reproduce the absolute counts of an experiment. Further, a gap exists between theoretical predictions for the performance of quantum-sensing systems and experimental results. This work bridges that gap with a simulation method for quantum-sensing with undetected light which includes experimental imperfections. For this, a theoretical approach is developed, and its capabilities are demonstrated with the simulation of aligned and misaligned quantum-imaging experiments. The results recreate the characteristics of the experimental data and are used to identify errors in experimental setups. The presented methods are broadly applicable and provide a step toward powerful simulation tools for quantum-sensing systems.