What active spin means
Every pitch spins around an axis. Active spin is the part of that rotation that runs across the ball's path, the way backspin or topspin does. That's the spin that creates the Magnus effect and moves the pitch up, down, or sideways. The other part is gyro spin, where the ball rotates around the direction it's traveling. Gyro spin is the bullet or football-spiral spin, and on its own it does little to move the ball.
Active spin is often a better guide to movement than total spin rate. Two fastballs can both spin at 2,300 rpm. If one is 95 percent efficient and the other is 75 percent, the first has about 2,185 rpm of active spin and the second about 1,725. The first will ride more and can look like it's rising to the hitter. The second will drop more on its way to the plate, even though both read the same spin rate.
Different systems show active spin in different ways. PitchLab shows it in rpm and shows the percentage separately as spin efficiency. Some other tools report active spin as a percentage, which is the same thing as spin efficiency. Whatever the label, it tells you how much of the spin is working to move the ball. For most fastballs and curveballs, more active spin means more movement.
Video explanation
Jake Fishman, PitchLab’s co-founder and CEO, pitched in the major leagues for the Miami Marlins. Here he explains active spin and what it means for your pitching.
What affects active spin
Total spin rate
Active spin can never be higher than total spin. More total spin raises the ceiling.
Spin efficiency
Efficiency sets how much of the total spin becomes active. A pitch at 95 percent keeps nearly all of it, and one at 40 percent keeps less than half.
Hand position at release
Fingers directly behind the ball tend to produce clean backspin and high active spin. When the hand drifts to the side of the ball, more of the spin turns into gyro.
Forearm rotation
Some pitchers naturally turn the hand outward through release and others turn it inward. That tendency shapes which pitches come out with the most active spin.
Grip and seam orientation
How the fingers sit on the seams changes the spin axis. A small grip change can shift a pitch from mostly gyro to mostly active spin, or back.
Pitch type
Four-seam fastballs want as much active spin as possible. Gyro sliders are built on low active spin, so the right number depends on the pitch.
What’s a good active spin?
| Pitch type | Average | Good | Great | Excellent |
|---|---|---|---|---|
| Four-seam fastball | 2,100 | 2,250 | 2,400 | 2,500+ |
| Sinker / two-seamDepends on pitch shape | 1,850 | 1,950 | 2,050 | 2,150+ |
| ChangeupLower is better | 1,600 | 1,450 | 1,300 | ≤1,150 |
| Curveball | 1,800 | 2,000 | 2,200 | 2,400+ |
| Sweeper | 1,300 | 1,500 | 1,700 | 1,900+ |
| Gyro sliderLower is better | 600 | 475 | 350 | ≤250 |
Estimates built from typical MLB spin rates and efficiencies, so use them as a guide. Changeups play better with less active spin because they get less lift and drop more than the fastball. Gyro sliders are built on bullet spin, so a low number is the goal. Sinker targets depend on the shape the pitcher wants.
How PitchLab measures it
PitchLab shows active spin in rpm on every pitch, right next to total spin rate and spin efficiency. It's measured with an iPhone on a tripod about 2 ft behind the pitcher, so you can compare it pitch by pitch and session by session as you work on a grip.
Active spin FAQs
How do you measure active spin with your phone?
Set an iPhone 12 or newer on a tripod about 2 ft behind the pitcher, facing home plate, and start a session in PitchLab. PitchLab shows active spin in rpm on every pitch, next to total spin rate and spin efficiency.
Is there an app that measures active spin?
Yes. PitchLab measures active spin with just an iPhone and a tripod, no sensors or smart ball needed. PitchLab is free to start.
What’s the best app for improving active spin?
Pick an app that shows active spin, total spin, and spin efficiency together on every throw, so you can see how much of your spin is working as you adjust a grip. PitchLab shows all three on every pitch with its video.
What is the difference between active spin and spin rate?
Spin rate is the total number of times the ball rotates per minute. Active spin is only the part of that rotation that moves the ball. A 2,400 rpm fastball at 85 percent efficiency has about 2,040 rpm of active spin. The rest is gyro spin, which adds little movement.
What is a good active spin for a fastball?
At the MLB level, a four-seam fastball typically has around 2,100 rpm of active spin, and 2,500 rpm or more is excellent. High school fastballs often land around 1,500 to 1,900 rpm, since they're thrown slower and spin less. For a riding four-seamer, aim for 90 percent or more of the spin to be active.
Is active spin the same as spin efficiency?
They describe the same thing in different units. Spin efficiency is the percentage of spin that is active. Active spin in rpm is that percentage applied to the total spin rate. Some tools use "active spin" to mean the percentage, so check which unit you're looking at.
How do you increase active spin?
You can add total spin, mostly by throwing harder, or raise spin efficiency so less of the spin is lost to gyro. For fastballs, that usually means getting the fingers more directly behind the ball at release. Small grip and seam changes can help. A pitch tracker shows right away whether a change worked.
