Stolen Base Success and Break-Even Calculator
Stolen Base Success and Break-Even Calculator
Steals divided by attempts, the net runs that record produced, and the success rate at which an attempt stops paying for itself. The break-even rate is derived from run values rather than chosen, and the three published figures — 75%, 70% and 66.7% — disagree for a reason this page can show you in one field.
Success rate, net runs, break-even
Steals ÷ attempts30 steals and 8 times caught, valuing a steal at 0.169 runs and a caught stealing at 0.394 runs
A rate, a break-even, and three published numbers that disagree
Net runs = SB × (runs a steal gains) − CS × (runs a caught stealing costs)
Break-even rate = (runs a caught stealing costs) ÷ (runs a steal gains + runs a caught stealing costs)
- where it comes from
- set the net runs to zero and solve. DRaysBay works exactly this algebra for a different baserunning decision — “solving for x where x is our runners chance of making it safely to third” — and the solution is the loss over the sum of the gain and the loss. Nothing is fitted: give it two run values and it returns one rate
- three published break-evens, 75%, 70% and 66.7%
- MLB’s glossary offers 75% with no working; FanGraphs measured +0.169 and −0.394 and derived 70%, or 71% excluding double steals; its own library stipulates a flat .2 for the steal and offers “at least twice as many SB as CS”, which is 66.7%. The table below sets each beside its derivation
- what none of the three is
- a figure for one attempt. A break-even for one runner on one base with one number of outs is a difference of two run expectancy values for that exact state, and it moves a long way between states — the DRaysBay author tried one for a single steal, got a figure he knew was too low, then a negative one, and published the failure rather than a number
Worked example
30 steals and 8 times caught, valuing a steal at 0.169 runs and a caught stealing at 0.394 runs
Attempts = 30 + 8 = 38, so the success rate = 30 ÷ 38 = 78.9%
Break-even = 0.394 ÷ (0.169 + 0.394) = 70.0% — FanGraphs' published figure, reproduced from its run values rather than quoted. So this record is 9.0 percentage points clear, with net runs of 30 × 0.169 − 8 × 0.394 = +1.92
Change the steal to the 0.200 its own library stipulates and the break-even FALLS to 0.394 ÷ 0.594 = 66.3% — that library's “twice as many steals as times caught”. One field moves the published answer by nearly four points
Double both run values, to 0.338 and 0.788, and the break-even does not move: 0.788 ÷ 1.126 is 70.0% again — it depends on the ratio, not the size. The NET RUNS do double, to +3.84
Double the steals and times caught, to 60 and 16, and the rate does not move: 60 ÷ 76 is 78.9%. Only the mix matters, which is what makes it a rate
Take the steals to 26 and times caught to 12 and the record drops below break-even: 68.4% against 70.0%, with net runs negative at −0.33
Set both to 0 and the page returns nothing rather than a zero: a success rate over no attempts does not exist
Three published break-even rates
| Source | Break-even | Where the number comes from | What it assumes |
|---|---|---|---|
| MLB’s glossary | 75% | a rule of thumb — “an SB% of 75 or higher is typically helping his team” | no derivation at all |
| FanGraphs, measured | 70%, or 71% excluding double steals | its own play-by-play run values, +0.169 for a steal and −0.394 for a caught stealing | a league-wide average across every base-out state |
| FanGraphs’ library | 66.7% | a flat .2 runs for a steal, and “twice as many SB as CS” | the steal stipulated rather than measured |
| Any single attempt | none of these | two run expectancy values for that exact base-out state, subtracted | a matrix for one park and one season, which this site does not carry |
The two run values
| Runs a steal gains | Runs a caught stealing costs | |
|---|---|---|
| FanGraphs’ measured value | 0.169 | 0.394 |
| FanGraphs’ library value | 0.200, stipulated for all seasons | two times runs per out, plus 0.075 |
| That formula at a runs-per-out of 0.160 | — | 0.395 |
| Changes between seasons? | the library says no; the blog measures one | the library says yes, explicitly |
| Break-even implied, other column at its measured value | 70.0% at 0.169, 66.3% at 0.200 | 70.0% at 0.394, 78.0% at 0.600 |
A break-even is a difference of two run expectancy values, so it is a field and not a constant
Stolen-base percentage is the simplest figure here and the only one a governing body defines: it “is determined by the number of steals for a player divided by his total number of attempts”, in MLB’s glossary’s words. Two things are not in it. A pickoff is scored separately from a caught stealing and does not reach a published stolen-base percentage, so it does not reach this one; and nothing in the percentage says whether the attempts were worth making, which is what the rest of this page is about.
The break-even rate is not a convention — it is a solved equation. An attempt gains runs when it works and costs runs when it fails, so the expected change is the success rate times the gain less the failure rate times the cost. Set that to zero and the break-even rate is the cost over the sum of the cost and the gain. DRaysBay works this algebra for a runner tagging up — “solving for x where x is our runners chance of making it safely to third” — and reaches 71% for a runner on second with one out. It sits well above half because the outcomes are not symmetrical: a steal advances a runner one base, a caught stealing removes him and spends an out. MLB’s glossary puts it without numbers — “a caught stealing is much more harmful than a stolen base is helpful”.
The two FanGraphs figures look like a publisher contradicting itself and they reconcile exactly. 0.394 ÷ (0.200 + 0.394) is 66.3%, so the library’s “twice as many steals as times caught” follows from its own stipulated coefficient to within half a point, and the whole gap from 70% is a steal measured at 0.169 against one stipulated at 0.200. The costs agree too: the library computes the caught-stealing value as two times runs per out plus 0.075, which at a runs-per-out of 0.160 returns 0.395 against the blog’s measured 0.394. MLB’s 75% arrives with no working at all.
A run expectancy matrix is twenty-four numbers: eight arrangements of baserunners against three out states, each holding the average runs a team went on to score from that position in the inning. There is not one matrix. FanGraphs, which publishes the clearest public explanation of it, says the matrices are “unique ones for each park and year based on run scoring”, and the example in its own glossary is described as “roughly neutral for 2014” at 4.15 runs a game. The footer of that same site records its Run Expectancy data as “licenced from TangoTiger.com”. This site therefore reproduces no value from any run expectancy matrix: a licence demonstrably exists and its terms were not read, this engine has no table lookup of any kind, and a fitted stand-in would be wrong at precisely the base-out states a decision turns on. That is why both run values here are fields with published defaults. Given the matrix for your park and season, the gain is the state the runner would reach less the state he starts in, the cost is the starting state less the state after he is out, and this page does the division. What such a matrix is, and why this site reproduces none of it, is on the run expectancy explainer; the same pattern is what athletics’ age-graded page does with its own published factor tables.
What this page will not tell you is whether a particular attempt was a good idea. The break-even above is a league average over every base-out state, and the author who measured it says so: “There are stolen base attempts with a breakeven well below 70%, and ones with a breakeven above it”, and “Maybe the breakeven rate is a bit different than my estimate.” A steal of third with two outs and one of second with nobody out are different decisions. Nothing here is a projection either: the net-runs figure describes a record already set, as the Pythagorean expectation calculator describes a season already played. For the batting figures beside a stolen-base line on the same record, see the batting average, OBP and SLG calculator and the isolated power calculator.
Frequently asked questions
What is the break-even stolen base success rate?
About 70% on FanGraphs’ measured run values of +0.169 for a steal and −0.394 for a caught stealing, or 71% excluding double steals. MLB’s glossary offers 75% with no derivation; FanGraphs’ own library implies 66.3%, stipulating the steal at .2 runs.
How is the break-even rate calculated?
Set the expected run change to zero and solve: the break-even rate is the cost of being caught over the sum of that cost and the gain. With 0.394 and 0.169 that is 70.0%. It depends only on the ratio, so doubling both leaves it unchanged.
Why does this page ask me for the run values?
Because each is a difference of two run expectancy values, and those matrices are, in FanGraphs’ words, “unique ones for each park and year based on run scoring”. There is no single correct pair. The defaults are that publisher’s measured figures, corroborated by a second page of its own.
Why is a caught stealing worse than a stolen base is good?
A steal advances a runner one base while a caught stealing removes him and spends an out, and an out is scarcer than a base. MLB’s glossary states it qualitatively: “a caught stealing is much more harmful than a stolen base is helpful.” Hence a break-even above half rather than at it.
Does the break-even rate change with the situation?
Yes, substantially. The figure here is a league average across all twenty-four base-out states; a break-even for one runner on one base with one number of outs needs that park and season’s run expectancy values, and this site reproduces no matrix. The author who measured it says individual attempts run well below and above it.
Are pickoffs included in a stolen-base percentage?
No. A pickoff is scored separately from a caught stealing and does not appear in a published stolen-base percentage, so it is not here either. A runner picked off repeatedly keeps a flattering rate.
Related calculators
References
- Major League Baseball. Glossary: Stolen-base Percentage (SB%) — “Stolen-base percentage is determined by the number of steals for a player divided by his total number of attempts.” Its rule of thumb is that “an SB% of 75 or higher is typically helping his team”, and it states qualitatively that “a caught stealing is much more harmful than a stolen base is helpful” while giving no run values, no break-even figure and no rule number. mlb.com (read 15 Oct 2026).
- “Breaking Even Is for Suckers.” FanGraphs, blogs.fangraphs.com — measures the average run value of a successful steal at +0.169 runs and of a caught stealing at -0.394, and concludes “Do the math, and that means that a 70% success rate has zero expected value. Exclude double steals from the analysis, and it’s about 71%.” It is explicit that this is a league-wide average and not a per-attempt figure — “There are stolen base attempts with a breakeven well below 70%, and ones with a breakeven above it” — and that “Maybe the breakeven rate is a bit different than my estimate.” The run values come from the site’s own play-by-play database; the FOOTER of the same site records its Run Expectancy data as “licenced from TangoTiger.com”, with play-by-play credited to Sports Info Solutions and Retrosheet (read 15 Oct 2026).
- FanGraphs Library. wSB — “wSB = (SB * runSB) + (CS * runCS) – (lgwSB * (1B + BB + HBP – IBB))”, where “the run value of a stolen base is set at .2 runs for all seasons” and “runCS = – (2 x RunsPerOut + 0.075)”, which “changes from year to year to reflect the changing value of runs and outs over the season”. Its own rule of thumb is that “you want to have at least twice as many SB as CS to break even”, which is 66.7% and not the 70% its own blog derives; the page attributes the rule of thumb to nobody and says only that it “bounces around based on the run environment”. library.fangraphs.com (read 15 Oct 2026).
- “Calculating baserunning break even points.” DRaysBay, 9 August 2020 — sets out the algebra this site reproduces: “Let’s do algebra, solving for x where x is our runners chance of making it safely to third”, worked as “.221*x – .549*(1-x) = 0” to give 71% for a runner on second with one out tagging up to third. Its run expectancy values are taken from “the RE24 table published in the FanGraphs glossary from 2014”, so it is NOT an independent source for those numbers. Recorded here because the author attempted a stolen-base break-even from the same table, got a figure he knew was too low and then a negative one, and published the failure — which is the clearest available evidence that a break-even depends on the exact base-out state and not on a league average. Its tables came through as text, not images (read 15 Oct 2026).
- FanGraphs Library. RE24 — defines RE24 as “run expectancy based on the 24 base-out states” and run expectancy as what “provides the average number of expected runs per inning given the current number of outs and placement of baserunners”. It states that the matrices are “unique ones for each park and year based on run scoring” and that RE24 uses “the run expectancy matrix for the given park in a particular year”; its displayed example is described as “roughly neutral for 2014” at 4.15 runs a game, and a win is worth “between 9 and 10 runs depending on the year”. A full 24-state matrix DID come through as real text rather than as an image. NO VALUE FROM IT IS REPRODUCED ON THIS SITE: the footer of the same site records its Run Expectancy data as licensed from TangoTiger.com, and that licence was not read. library.fangraphs.com (read 15 Oct 2026).