Understanding Hitman's scoring system is just as complex as pulling off a stealth kill.
After completing a mission, the game considers many factors when tallying your score. Some of those aren't as straightforward as they appear in the Debriefing page. Below, you'll find definitions of the variables that add up to your final score.
Awarded for completing the main mission.
Note that some Contracts missions like "Do Me I Dare You" require you to complete the main story objectives to get credit for this, while Contract missions like those in The Sarajevo Six do not. The rule of thumb is that if you don't hear your handler's voiceover at the start of a Contract, you will need to complete the main mission to get the Objectives Completed credit.
Simply put, blend in and never arouse suspicion. Detection rings can appear without penalty as long as the triangle on the ring doesn't reach full size.
No Noticed Kills
Awarded for killing without witnesses. If you kill in front of a witness, killing the witness will not help.
No Bodies Found
You might've pulled off your kill without witnesses, and you might have long since left the scene of the crime, but as long as the body is out in the open, you won't achieve the best score. Someone will see the evidence of your crime.
This is what trunks and wardrobes are for. Use them to hide bodies.
The modern world is filled with countless surveillance cameras. It would be a challenge to navigate through Hitman's maps while being truly invisible, avoiding all the camera-equipped rooms.
If there is a camera system, then there's a surveillance room somewhere. Find that room, and disable the electronics to erase your video recorded existence.
Non-Target Kill Penalty
You're there for the targets and the targets only — unless you're truly coldblooded. Hitman does offer a number of Challenges where you can't avoid collateral damage. Ignore those Challenges to avoid penalization. If you do everything right, you'll see zero points deducted for the Non-Target Kill Penalty.
Getting the highest possible score based on time isn't as clear cut as completing the mission as soon as possible. Hitman values your attempts at total stealth, so pulling off any of the above goals will factor in the Time Bonus score.
You can earn more than 55,000 Time Bonus points for taking 17 minutes to complete a mission, provided you pulled off the assignment with 100 percent stealth. Conversely, you'll earn no Time Bonus points for completing a mission in 5 minutes if you run-and-gun your way to your target.
Challenges Completed / Mission Mastery Earned
These do not factor into the main score, let alone the Silent Assassin award. Instead, these points feed into your Career Mastery Level, which unlocks new infiltration opportunities such as new item smuggling locations and new mission starting points.
Furthermore, the moment you complete one challenge, you cannot earn credit for it again. That means you can't level farm — but you can repeat the steps of a given challenge by replaying the mission. Note that some Challenges can be completed during your mission playthrough.