Calcode is a solver for ordinary differential equations (ODE).

The ODEs are entered symbolically, and the solution is exhibited numerically and graphically, in an interconnected way, like so.

You can easily analyse the solution, find zeros, and extrema, make phase plots, or compare with a known symbolic function.

You can also do a 3d animation of the solution, like so

Calcode allows one to solve tough problems of Newtonian physics in a jiffy. This is an educational tool to teach to schoolchildren topics conventionally regarded as advanced, such as Jacobian elliptic functions, or Ballistics with air resistance. I used this with my kids to clarify the conceptual confusion in physics text between pendulum motion and simple harmonic motion. The software was first built on DOS, and then it incorporated 3d animation.

The software is available free for personal use, but requires a license. If you are interested in it, download it, and install. On first use it will generate a couple of text files which you need to email to me at to get back a license file in due course. The install files are msi files for Windows installer on Windows XP, and Vista. I do have some older install files appropriate for Windows 2000 and 98, and even DOS 3.1! If you need those, let me know, and I will search for them and upload them.

For more details check out the documentation, and also the article in Science and Education on "Time: What is it that it can be measured?, and also the pendulum project at


Time: What is it that it can be measured? Science & Education, 15(6) (2006) pp. 537–551 DOI 10.1007/s11191-005-5287-z. (International Pendulum conference 2005)

Pendulum project


"Calculus without Limits"  teaching project


Install files Version 3.33

  • The new version of Calcode installer file includes the right help files and beginner's guide.
  • Calcode (For Windows XP and lower(?), 4.8 MB)

Don't have Windows installer? Download these: