Baseball Stolen Base Percentage Calculator
Calculate SB%, net stolen bases, break-even rate & runs added
Stolen Base Stats Calculator
Enter SB and CS to calculate all baserunning metrics.
📊 MLB Stolen Base Percentage Benchmarks
| SB% Range | Rating | Team Impact | MLB Examples |
|---|---|---|---|
| > 80% | Elite | Clearly positive run contribution | Rickey Henderson, Tim Raines, Trea Turner |
| 70 – 80% | Good | Moderate positive run value | Most quality MLB base stealers |
| 65 – 70% | Borderline | Near-neutral; situational value | Marginal base stealers |
| < 65% | Hurts Team | Negative run contribution | Should reduce steal attempts |
⚾ The 66.7% Break-Even Rule
A runner must succeed on more than 2 out of every 3 steal attempts to add net value. Below 66.7%, the outs sacrificed by being caught stealing cost more runs than the bases gained by successful steals. Linear weights place the exact value at approximately SB × 0.175 − CS × 0.467; positive = helps the team.
Formulas Reference
Stolen Base %
SB% = SB ÷ (SB + CS) × 100
CS = Caught Stealing
Net Stolen Bases
Net SB = SB − CS
True bases gained after accounting for caught stealing
Break-Even Rate
Break-Even ≈ 66.7% (2/3)
Minimum SB% to add positive value to team
Runs Added (Linear Weights)
Runs = SB × 0.175 − CS × 0.467
Simplified run value estimate; positive = helps team
What is Stolen Base Percentage?
Stolen base percentage (SB%) measures how efficiently a baserunner steals bases. It is expressed as the fraction of steal attempts that result in a successful stolen base. Unlike raw stolen base totals — which can be inflated by a player who simply attempts many steals regardless of success — SB% controls for attempt frequency and tells you how reliably the runner converts opportunities into advances.
In modern baseball analytics, SB% is evaluated alongside the number of attempts, because a player who attempts 50 steals at 80% success contributes more run value than a player who attempts 5 steals at 80%. Together, attempt volume and success rate paint a complete picture of baserunning quality.
How to Calculate Stolen Base Percentage
The formula is:
Worked Example: A baserunner has 30 stolen bases and is caught stealing 10 times in a season.
- Total Attempts = 30 + 10 = 40
- SB% = 30 ÷ 40 × 100 = 75.0%
- Net Stolen Bases = 30 − 10 = +20
- Runs Added = (30 × 0.175) − (10 × 0.467) = 5.25 − 4.67 = +0.58 runs
This runner is above the 66.7% break-even threshold and provides a small but positive run value contribution through stolen bases.
The 66.7% Break-Even Rule Explained
The 66.7% threshold comes from the run-expectancy cost of being caught stealing versus the benefit of a successful steal. An out is one of the most costly events in baseball — it eliminates a baserunner and costs the team approximately 0.47 expected runs. A successful stolen base of second is worth roughly +0.17 to +0.20 runs, depending on the run environment and the specific base state. Solving for the break-even point:
Using these specific linear weights, the exact break-even is closer to 72–73%, though the commonly cited round number of 66.7% (two-thirds) is used as a simple and conservative benchmark. The key takeaway: stealing bases is only beneficial when done with high efficiency.
Net Stolen Bases and Run Value
Net stolen bases (SB − CS) is the simplest way to assess whether a player's baserunning helped or hurt the team. A positive net means the player gained more bases than they gave back in outs. However, because caught stealing is more costly than a stolen base is valuable, a player can have a positive net stolen base total while still having a slightly negative run value. The linear weights formula — SB × 0.175 − CS × 0.467 — accounts for this asymmetry and provides a more accurate estimate of run contribution.
Historical Context and Modern MLB Trends
Stolen base attempts declined significantly from the aggressive 1980s era through the 2010s as the "three true outcomes" philosophy (walk, strikeout, home run) dominated offensive strategy. However, the 2023 introduction of larger bases and the pitch clock in MLB sparked a resurgence in stolen base activity, with league stolen base totals rising to their highest levels in over a decade. Top speedsters like Ronald Acuña Jr., Elly De La Cruz, and Trea Turner have re-established the value of elite baserunning in the modern game.