Two options: Simple ISO Calculator that uses SLG and AVG (in decimal form), or an Expanded ISO Calculator that uses 2B, 3B, HR, and AB’s. Both tools calculate Isolated Power but use different stat inputs.
Simple ISO Calculator
Expanded ISO Calculator
How to Use These ISO Calculators
Simple ISO Calculator for Baseball
To use this simpler Isolated Power Calculator, start by entering the slugging percentage (SLG) in the first box. Next, enter the batting average (AVG) in the second box. Then, click Calculate ISO to see the result.
A player with a slugging percentage of 0.450 and a batting average of 0.275 would enter 0.450 in the first box and 0.275 in the second box. The calculator subtracts the batting average from the slugging percentage to find the ISO. The result in this case is 0.175.
This calculator works best when slugging percentage and batting average are already available. It provides a quick way to measure how much of a player's slugging percentage comes from extra-base hits. This method is useful for fast comparisons between players without needing detailed hit data.
Expanded ISO Calculator for Baseball
To use this expanded Isolated Power Calculator, start by entering the number of doubles in the first box. Next, enter the number of triples in the second box. Enter the number of home runs in the third box. Enter the number of at-bats in the last box. Finally, click Calculate ISO to see the result.
A player with 10 doubles, 5 triples, 20 home runs, and 400 at-bats would enter 10, 5, 20, and 400 in the respective boxes. The calculator applies a formula that weights triples and home runs before dividing by at-bats. The result in this case is 0.200.
This calculator works best when slugging percentage and batting average are not available but detailed hit data is. It allows for more flexible calculations and can be useful when tracking power numbers for different leagues or manually calculating ISO.
ISO Chart
| ISO Range | Grade |
|---|---|
| Below 0.080 | Below Average |
| 0.080 - 0.139 | Average |
| 0.140 - 0.199 | Good |
| 0.200 and above | Great |
What is a good ISO in baseball?
A good ISO in baseball is in the 0.140 - 0.199 range. This can vary by what era of baseball you are evaluating.
ISO has historically been used to measure a player's raw power by focusing only on extra-base hits. League-wide ISO averages have varied over time, often influenced by changes in offensive environments, ballpark dimensions, and league-wide approaches to hitting.
In Major League Baseball, the average ISO typically falls between 0.140 and 0.160, with power hitters often exceeding 0.200. During the dead-ball era, ISO values were significantly lower, reflecting a style of play centered around contact hitting and stolen bases.
In contrast, the modern game, especially in the home run-heavy eras of the late 1990s and early 2000s, has seen ISO values rise as players focus more on power and launch angle. Historically, players with an ISO above 0.250 are considered elite power hitters, while those below 0.080 tend to be contact hitters with little extra-base power.
ISO Formula in Baseball
How to figure ISO in baseball?
As I discussed earlier in the article, there are two ways to calculate ISO in baseball. A simpler way, and a more expanded way. These are the ISO formulas in baseball:
Simple ISO Calculator Formula:
ISO = SLG - AVG
Expanded ISO Calculator Formula:
ISO = (Doubles + (2 × Triples) + (3 × Home Runs)) ÷ At-Bats
The simple formula provides a quick estimate when slugging percentage and batting average are available, while the expanded formula calculates ISO directly from hit data. Both methods measure a player's power, but the expanded formula is useful when detailed hit statistics are available, making it more flexible for different levels of play.
Why ISO Matters and What It Measures
Calculating ISO in baseball measures a hitter’s raw power by isolating extra-base hits from overall batting performance. In contrast, batting average counts all hits equally, but ISO focuses only on doubles, triples, and home runs.
A high ISO means a player consistently produces extra-base hits, which directly contributes to run production. Power hitters typically have high ISO values because they drive the ball into the gaps or over the fence, creating more scoring opportunities for their team.
The problem with batting average is it alone does not separate a slap hitter from a power hitter. A player with a .300 batting average might hit mostly singles, while another with a .250 batting average might hit home runs at a much higher rate.
ISO highlights the difference between these two players by measuring the extra-base hit power that batting average does not capture. A player with a high batting average but a low ISO often relies on singles and may not drive in many runs, while a player with a lower batting average but a high ISO likely contributes more runs by hitting for power.
Because ISO focuses only on power production, it tells a better story about a hitter’s ability to create offensive value than batting average alone. A quick way to determine a player's power production is by using our ISO calculators to determine a hitter's ability to generate extra-base hits.
How Other Hitting Metrics Help Complete the Picture
ISO provides valuable insight into power, but it does not tell the full story of a hitter’s offensive value. A player with a high ISO may be a powerful slugger, but if they struggle to get on base, their overall value may be lower than their power numbers suggest.
Other metrics like OPS, wOBA, and OBP help paint a clearer picture of a player's offensive contributions by including on-base skills and overall hitting efficiency. OPS, which combines on-base plus slugging percentage, balances power and the ability to reach base.
A player with a strong OPS is not only hitting for extra bases but also avoiding outs and extending innings. wOBA (weighted on-base average) takes this further by assigning different values to each type of hit and walk, providing a more accurate measurement of a player’s total offensive impact.
This Isolated Power calculator is an effective tool for analyzing offensive value, but pairing ISO with OBP and SLG gives a more complete evaluation of a hitter. A player with a high ISO but a low OBP may be an all-or-nothing slugger who relies heavily on home runs but does not reach base consistently.
In contrast, a player with a solid ISO, OBP, and SLG is likely a well-rounded hitter who provides power while also getting on base at a high rate. By calculating ISO alongside these other metrics, teams and analysts can better understand a player’s strengths, weaknesses, and overall offensive value.