How Current Score is calculated  formula
Current Rankings are based on the Current Score of each fighter.
Every week Current Score is recalculated for all fighters.
Four different scoring methods are combined to compute the Current Score (CS, CurScr).
Following is the main Current Score formula:
CurrentScore = CareerScore*60% + MidTermScore + RecentScore + Last4Fights + StreakPoints
Different algorithms are used for each component (separately calculated scores) and they are based on the logic defined by 4 different scoring methods.
First component is the Career Score and only 60% of that value is used to calculate Current Score. When we used 100% of the Career score, veteran fighters were having unrealistic Current Scores.
This gives us an approximate distribution of 1/5 + 1/4 + 1/4 + 1/4 for each scoring method.
Here are typical numbers for Current Score and scores for other scoring methods:
max possible 
max now 
good score 

Current Score 
1200 
990 
600 

Career (A) 
320 
290 
200 
20% 
Midterm (B) 
320 
260 
150 
26% 
Recent (C) 
320 
260 
140 
26% 
Last 4 (D) 
320 
260 
140 
26% 
Streak 
40 
30 
10 
2% 
max possible  is a maximum theoretically possible score.
max now  The max score achieved by a fighter so far.
good score  is what a very good fighter (not excellent) typically gets.
Only a handful of fighters (in the whole MMA history) were able to get over 900 points for CurrScore. Here is a graphical example for some of them:
Going above 800 points happened in the career of just about 60 fighters.
Less than 300 fighters were able to have CurScr > 600 at some point in their career.
Number of different variables are used to calculate those scores.
Some variables are used in all scoring methods and some are exclusive to one method. Variables are used in various formulas to create descriptive measures. Those measures are then used to calculate scores.
The most significant measures (typically used in every rating system) are:
 Win/Loss ratios
 Opponents' ratings
 Individual score from each fight
On top of that we are adding other measures (related to performance, events, titles, etc).
Win/Loss Ratio calculation
We start calculating the Win/Loss measure with the standard win percentage (max=100%) and then enhance that percentage to avoid some abnormalities (like giving 100 points to beginners with 50 or even 20 record).
In addition, we have calculated several measures that are based on the Win/Loss record against just the Good/Top fighters and record in the big shows (important promotions). These are all added together to calculate the final Win/Loss part of the score.
Opponent related calculations
To calculate the points that are received from the Opponents that the fighter has faced, we are using a number of different variables. The most commonly used variables are:
 Average Opponent Rating (average rating for all opponents)
 Average Opponent Rating for Wins (average rating of all opponents that they defeated)
 Sum of Opponent Rating for Wins (this is to complement average rating, since somebody that had only 1 fight might have an unwarranted big average, while it awards additional points to more active fighters)
 Weight Difference (if somebody is fighting larger opponents. This was more prevalent in the past)
Also, we created additional measures that deal only with the Top Opponents. All fights with low rated opponents are eliminated and then those measures for good opponents are calculated.
When calculating for methods that have a longer timeframe (like Career Score), we use Opponents Career Rating, and for the Recent Score, Current Rating is used.
Calculating score for individual fight
The following are the components that are used in this calculation:
 Opponent Current Ranking and Current Score
 Win/Loss points (incorporate Opponents Career Rating and some Fight Marks)
 End Method, Event points, difference in weight
 Fight Marks  evaluation based on fighter performance in that fight