Reach Advantage Calculator
Calculate the reach advantage between two fighters from arm span, height, and stance.
Quantify the striking range edge for MMA, boxing, and kickboxing bouts.
What is reach and why it matters:
Reach (or arm span) is measured fingertip to fingertip with arms extended horizontally. In combat sports, reach determines who can strike first from distance. A fighter with longer reach can land jabs and front kicks while staying outside their opponent’s effective range.
Reach vs. height ratio:
Most people have an arm span roughly equal to their height (a 1:1 ratio, called the “Vitruvian” proportion). Fighters with a positive ape index (reach greater than height) have a natural distance advantage.
Ape Index = Reach - Height
| Ape Index | Classification | Advantage |
|---|---|---|
| < -5 cm | Short reach | Must close distance aggressively |
| -5 to 0 cm | Average | Neutral |
| 0 to +5 cm | Above average | Slight jab range advantage |
| +5 to +10 cm | Long reach | Strong distance control |
| > +10 cm | Exceptional | Elite-level reach (like Jon Jones at +26 cm) |
Effective striking range formula:
Jab range = (Reach / 2) × 0.95 + Shoulder width × 0.3
Cross range = (Reach / 2) × 1.05 + Shoulder width × 0.5
These account for shoulder rotation. A cross extends further than a jab because the rear shoulder drives forward.
Reach advantage between two fighters:
Raw reach advantage = Fighter A reach - Fighter B reach
Effective advantage = Raw advantage × Stance modifier
| Stance Matchup | Modifier | Reasoning |
|---|---|---|
| Orthodox vs Orthodox | 1.0 | Standard |
| Southpaw vs Southpaw | 1.0 | Standard |
| Orthodox vs Southpaw | 0.85 | Open stance reduces pure reach advantage |
| Switch-hitter | 0.90 | Can neutralize by matching stance |
Example calculation:
Fighter A: 188 cm tall, 198 cm reach (Orthodox) Fighter B: 183 cm tall, 185 cm reach (Orthodox)
- Raw advantage: 198 - 185 = 13 cm
- Effective advantage: 13 × 1.0 = 13 cm
- Fighter A ape index: 198 - 188 = +10 cm (exceptional)
- Fighter B ape index: 185 - 183 = +2 cm (average)
Tactical implications by advantage size:
- 0–5 cm: Minimal difference. Technique and timing matter more than reach.
- 5–10 cm: Noticeable advantage. Longer fighter can maintain distance with jabs.
- 10–15 cm: Significant. Shorter fighter must use head movement and angles to close distance.
- 15+ cm: Dominant. Shorter fighter typically needs wrestling or clinch work to negate reach.