RE24 is quite simple to use for hitters if you’re already familiar with runs above average numbers like wRAA. With league average set to zero, any positive value is that many runs above average and some other negative value is that many runs below average. RE24 comprises batting and between at bat baserunning (stolen base, wild pitches, etc), so if a player has 30.5 RE24, so they were about 30 runs better than the average player could have been if given the very same opportunities. Each win is worth between 9 and 10 runs depending on the year, so you can convert RE24 into wins by dividing it by that year’s runs each win. On FanGraphs, we predict this REW instead of RE24.
Remember that RE24 is providing you with context adjusted conducts, so when studying this statistic you are measuring a player’s operation above or below average given the context in which they have been placed. If you would like to compare their circumstance neutral stats with their context adjusted stats, an easy trick is to compare RE24 into Batting Runs plus wSB (or OFF without UBR). This will allow you to see how well or badly calibrated a hitter’s performance was, but keep in mind, context dependent numbers are predictive of future performance than circumstance neutral ones.
For pitchers, using RE24 in the language of RA9 or ERA is a bit trickier. You could just learn to think in terms of runs above average for pitchers like you do for hitters, however, the choice is to consider about 0.46 runs per inning and subtract the pitcher’s RE24 total to see it in terms of runs allowed. Then in the event that you treat that new amount as conducts enabled and multiply be 9 and split by innings pitcher, then you’ll end up with something similar to RE24 on a per 9 inning scale. Remember that RE24 is based on the conduct environment and park so this won’t be perfect. Remember also that while allowing runs is bad, a positive RE24 is good since it’s a step of runs better than average for pitchers. For starters, you won’t typically see dramatic differences, but for relievers you may.
Furthermore, whilst RE24 controls for outs and baserunner placement, it does not make any adjustments depending on the score of the game or the inning, meaning that a bases loaded situation is the same in case the score is tied at the ninth inning or if the difference is seven runs in the fourth. To put it differently, while it controls for the probable amount of runs, it does not control for how important those runs may be in the context of this match. RE24 also doesn’t include any defensive value. All offensive events visit the hitter (or baserunner on steals) and all defensive events are credited to the pitcher. So while you may swap in RE24 to get Batting Runs + wSB, then you cannot look at a player’s RE24-Wins and call that WAR since it does not include all baserunning, any defense, any positional adjustment, or replacement degree.

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