Meep is a free and open-source software package for electromagnetics simulation via the finite-difference time-domain (FDTD) method spanning a broad range of applications.

Key Features

Time-Domain Simulation#

A time-domain electromagnetic simulation simply evolves Maxwell's equations over time within some finite computational volume, essentially performing a kind of numerical experiment. This can be used to calculate a wide variety of useful quantities. Major applications include:

  • Transmittance and Reflectance Spectra — by Fourier-transforming the response to a short pulse, a single simulation can yield the scattering amplitudes over a broadband spectrum.
  • Resonant Modes and Frequencies — by analyzing the response of the system to a short pulse, one can extract the frequencies, decay rates, and field patterns of the harmonic modes of lossy and lossless systems including waveguide and cavity modes.
  • Field Patterns (e.g. Green's functions) — in response to an arbitrary source via a continuous-wave (CW) input (fixed-ω).

Meep's scriptable interface makes it possible to combine many sorts of computations along with multi-parameter optimization in sequence or in parallel.

Tutorial/Basics provides examples of the various kinds of computations.


The source repository is hosted on GitHub. Gzipped tarballs of tagged versions are in Releases. The release history is in NEWS. Installation instructions are in Installation.


For a list of topics, see the left navigation sidebar. For new users, the most important items to review are the Introduction, Tutorial/Basics, and FAQ.

This documentation is for the master branch of the source repository. Note that certain features described in this documentation may therefore be unavailable if you are using a tagged release.

Discussion Forum#

For questions regarding setting up simulations, analyzing results, installation, etc., use the Discussions page on GitHub.

As an additional resource, archives of the meep-discuss mailing list, which is no longer active, are available which include postings from 2006-2021. These archives can also be accessed using a newsgroup reader via the NNTP interface address:

Bug Reports and Feature Requests#

For bug reports and feature requests, please file a GitHub issue.


The Meep project is maintained by the developer community on GitHub. Acknowledgements provides a complete listing of the project contributors.

Support and Feedback#

If you have questions or problems regarding Meep, you are encouraged to query the mailing list.