Play Them.

Gravity Simulator

Fling planets and change physics in this gravity sandbox. Play online for free, or get the full version for: fullscreen mode, faster calculations, more planet images, General Relativity, mod support, editable colors, and more.

Want to add 1000 planets? Go ahead.
Curious about Lagrange Points? Make em.
Hate the inverse square law? Change it.

Learn more about the full version.

Download it.



Grav. Grav. Grav. Grav. Grav. Grav. Grav. Grav. Grav.






What’s the difference between the Full Version and the Online Version?

The full version includes many more features than the online version. A quick list...

  • Much more powerful, can handle more planets
  • More planet images to pick from, or import your own
  • Test out arbitrary force laws
  • Set the potential, add in a tangential force, modify quality settings
  • General Relativity (black holes, two-body orbits, etc)
  • Customizable colors and lines
  • Speed up and slow down time
  • Track planets, seeing the world from their frame
  • Displays energy (kinetic/potential) of each object
  • And more. Oh, is there more.


I want it on mobile devices.

Me too. It’s coming.*

*it may be some time.



Release Notes


The simulator is a work-in-progress. If you find any bugs or desperately want and features, join in the discussion in the forums, get in touch with me, and help make the simulator even better.


Version 0.32.02

  • Released 9/23/16
  • Bug fixes, reduced file size.
  • more details

Version 0.32.01

  • Released 9/22/16
  • Added in elliptical trails, improved general relativity, etc.
  • more details

Version 0.32

  • Released 8/11/16
  • Lots of changes. New menus, new save code, new images, mod-support, etc.
  • more details

Version 0.31.01

  • Released 4/1/16
  • New Menus
  • New Orbit Line-system
  • more details

Version 0.29.03

  • Released 5/31/14
  • Transverse Forces
  • Rotation
  • Lagrange Tracking
  • more details

Version 0.29.01


Version 0.28.01

  • Released 5/1/14
  • Change length of orbits
  • Fling fixed stars
  • Arrows!
  • more details

Version 0.27.01

  • Released 4/17/14
  • New Menu system
  • Edit planets on-the-fly
  • more details

Version 0.26.03

  • Released 4/3/14
  • Extended the gravity force laws (+,-,*,/,^,sin,cos,tan)
  • Save/load code now loads force law, too
  • Crosshairs toggle-able
  • more details

Version 0.26.02

  • Released 3/31/14
  • Now supports multiple resolutions
  • Quit button added
  • Auto-updater fixed
  • Music!
  • Basic Instructions
  • more details

Version 0.26.01

  • Released 3/24/14
  • First full version!


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