Open BirdcageBuilder

An open-source, web-based, cross-platform inductance and capacitor calculator for building birdcage RF coils.

We are making available Open BirdcageBuilder, an open-source, web-based interface for calculating the fundamental design features of birdcage radio-frequency (RF) coils, common in MR imaging.

Birdcage RF coils are resonant circuits that operate with a specific current pattern at particular frequencies and are tuned by choosing the proper capacitor values.

Open BirdcageBuilder calculates mutual inductances and capacitors needed to make a coil resonate at a particular frequency, given the coil’s geometric properties such as the length and number of legs, cross-sectional shape of legs and end-rings, and the radii of the coil and shield.

The user-friendly, responsive interface runs in a web browser on any device with an internet connection.

Illustration of Open BirdcageBuilder on a mobile phone browser.
Open BirdcageBuilder interface on a mobile browser. Illustration: Pawel Slabiak/NYU Langone Health; Mateo Vella/Unsplash.

Related Publication

Chin CL, Collins CM, Li S, Dardzinski BJ, Smith MB.
BirdcageBuilder: Design of Specified-Geometry Birdcage Coils with Desired Current Pattern and Resonant Frequency.
Concepts Magn Reson. 2002 Jun;15(2):156-163. doi: 10.1002/cmr.10030

Please cite this work if you are using Open BirdcageBuilder in your research.

Open Source

We are sharing the source code for Open BirdcageBuilder via a Github repository at


Questions about this resource may be directed to Douglas Brantner, MS.

Related Resource

An older version of BirdcageBuilder that runs locally on Android devices is also available.