Habitability is a percentage that gives a general idea as to whether a planet can maintain a healthy colony. The lower the habitability percentage, the worse the conditions on that planet are. Habitability of a planet can be improved by Terraforming it.

Please note that 0% habitability is not an absolute bottom, but represents a cut off where a planet is considered extremely difficult to colonize. Some are still far worse than others. You should take a close look at such a planet before attempting colonization.

- Deviation from a gravity of 10 m/s². However, gravity below 10 m/s² is less problematic than higher gravity.
- Deviation from an average temperature of 15ºC.
- Any atmosphere that is not oxygen based. While some simply prevent people from breathing, others like hydrogen or acidic present much more severe hazards.
- Weather conditions.