These programs are learning tools.  They are NOT engineering tools.  They can give you an idea of what field strengths and shapes you might expect from magnets of different sizes and materials.  Actual design and engineering work requires a good knowledge of magnetic materials and appropriate software tools.  Free calculators on the internet are no substitute for experience and good software tools!  They can be a good starting point for learning more.  

If you are serious about magnet design work, you will need appropriate software tools to do it correctly.   You also need to have a good understanding of magnetic materials.  This software is based off of direct solutions of Maxwell's equations.  For magnets of the appropriate shape and material, these solutions are fairly accurate.  For magnets with inappropriate shapes for a given material, the solutions will not be accurate.  As a practical matter, direct solutions are often a reasonable approach to use for rare-earth and ceramic magnets if you clearly understand the limitations.

These programs are written using Mathematica.  They can be run using the free CDF Player program.  You will need to download and install CDF Player in order to use them.  Clicking the icon to the left takes you to the download page at www.wolfram.com.  

This simple tool looks at a single point near a cylinder magnet.  It should run smoothly and quickly on most computers.

The magnetization is along the cylinder axis.

This tool plots the axial and radial field components on a line parallel to the axis of a cylinder magnet.

This tool is somewhat computationally intensive.  It might take several seconds to regenerate the plots after you change the parameters.

The magnetization is along the cylinder axis.

This tool plots the axial and radial field components on a line perpendicular to the axis of a cylinder magnet.

This tool is somewhat computationally intensive.  It might take several seconds to regenerate the plots after you change the parameters.

The magnetization is along the cylinder axis.

This tool shows a vector plot of the cross-section of a cylinder magnet.

This tool is somewhat computationally intensive.  It might take several seconds to regenerate the plots after you change the parameters.

The color scaling ranges from 0 (purple) to whatever value red is set for.