Simulation Speed: Fast

sd.js leverages work by Google, Mozilla, and Microsoft in order to simulate models faster than ever before.

Modern web browsers like Firefox, Chrome and Internet Explorer have gotten very good at running JavaScript, the programming language that powers the web, very takes full advantage of this, running models in the web browsers orders of magnitude faster than current proprietary SD softare. On top of this, the user interface is designed to stay interactive and snappy, even while simulating monster models.


  • The simple model below has 10 million time steps, and runs in {{calculating}} seconds on your computer.
  • On my computer the model runs in 1.5 seconds, roughly 100x faster than Vensim (2.5 minutes) and 10,000x faster than STELLA (4+ hours).
  • Try it yourself - Vensim model | STELLA/iThink model