SWOLF, derived from swimming & golf, measures your performance in swimming. You'll get your SWOLF score by swimming one length of a pool and counting the number of strokes you take. You count the strokes from each hand. Use a timer to get your swim time in seconds. Then add your strokes to your time, for example 45 strokes + 55 seconds. The result is 100 and that is your SWOLF score. SWOLF scores from different pool sizes are not comparable: if your SWOLF score is 100 in a long course pool, it's about 50 in a short course pool.
You should only keep track of how your own SWOLF score develops and not compare it with your friends’ scores. Basically, the lower your score, the better your swimming performance.