FDTD++ is a finite-difference time-domain software platform for numerical simulations of Maxwell’s equations. Developed by active researchers and authors of FDTD methodologies, it is offered free with open C++ source code. The software supports simulations in three, two, or one dimension, with results available in the time domain, frequency domain, or both. It includes multiple boundary-condition options and advanced capabilities intended to improve applicability, accuracy, and computational efficiency.

FDTD++ provides flexible geometric modeling for computer-aided designs, meshes, and algorithmically specified structures, alongside sophisticated material models fitted to experimental optical data. Users can access data processing and post-processing tools and control simulation parameters through an interface described as powerful yet simple. The platform is designed to scale from desktop use to massively parallel simulations. Its supporting resources include a detailed instruction manual, examples, tutorials on both the software and FDTD methods, discussion forums, and email support. FDTD++ also offers consulting services. The website identifies Algorithms in Motion LLC as the copyright holder.