WiFi Solver FDTD

571 reviews
Content rating
Screenshot image
Screenshot image
Screenshot image
Screenshot image
Screenshot image

About this app

With this app you can take a floorplan of your house, set the location of a WiFi router, and simulate how the electromagnetic WiFi waves propagate.

See the app in action in the following video by tech news website The Verge:


This app is based on a post 'Helmhurts' at my blog 'Almost Looks Like Work', which was featured on Engadget, Ars Technica, and many other publications:


This app uses the 2D Finite Difference Time Domain (FDTD) method to solve Maxwell's equation on a Cartesian grid. An example floorplan is included in the app.

How to use:

Your floorplan needs to be a .png file, with empty space marked black and materials marked with colours. Images will be converted into the correct materials on loading - this may take a few seconds.

Pixels are mapped to 1 centimetre, so scale the floorplan appropriately.

The simulation is limited in speed due to the mobile processor, so try to keep images below approximately 1000x1000 pixels

Touch the image to set a router location, marked by a red circle. Select the antenna parameters at the bottom.

Choose what to plot - 'Field' is the instantaneous electric field amplitude, 'Flux' is the time-averaged magnitude of Poynting flux.

Click run and the simulation will begin. Click stop to pause at any time - this saves the simulation progress which can be continued by clicking run again. To reset, open an image again.

To save the simulation output as an image, click Save at any time. Images are saved to internal/external storage and added to the end of the camera roll.

To start recording a simulation click the record 'R' button. When the simulation is stopped a GIF animation is generated.

Under the bonnet:

An antenna oscillates at 2.4 GHz. The edges of the image use absorbing boundary conditions as in Mur 1981, IEEE Transactions on Electromagnetic Compatibility.

Where walls are defined, the relevant refractive indices and loss tangents for 2.4GHz radiation are used.


This app is not intended as a replacement for existing EM simulation software packages.
As a 2D approximation including only simple walls it may not accurately model a given floorplan.
Updated on
Nov 27, 2023

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
No data shared with third parties
Learn more about how developers declare sharing
No data collected
Learn more about how developers declare collection

Ratings and reviews

540 reviews
Pazik Bezstrashnyj
April 12, 2024
Please update, make this easier to use. At least the ability to change the scale. Sometimes it doesn't like starting.
Did you find this helpful?
Mario Brce
February 23, 2021
This app has literally saved me hundreds of dollars on unecessary wifi equipment and helped get the most of what I have on hand. While you do need to scale and colour your floorplan in another image editing program like photoshop for it to work well, once it's loaded up it has often saved me hours in awkward experimenting with wifi points and cables to find the perfect sweet spot. Awesome nerdware.
20 people found this review helpful
Did you find this helpful?
May 26, 2021
Thanks so much for the review! I agree that it would be much nicer to edit the floorplan in-app, but often it's quite a fiddly process best done elsewhere. Glad you've found it useful.
YiDa Seow
August 22, 2021
Really saved me a lot of time and experiments with this simulation, though 5g mapping would be good too. For multiple APs, you would just need to simulate with one AP at a time and then combine them together, since these APs would be running on multiple channels for the most of the setups (MCA).
8 people found this review helpful
Did you find this helpful?

What's new

Updated app to be compatible with latest Android SDK versions.