What spin rate means
Spin rate measures how fast the ball rotates after it leaves the pitcher's hand. It's reported in revolutions per minute, or rpm. A four-seam fastball at 2,300 rpm turns over about 38 times per second. That adds up to roughly 15 full turns before it reaches the plate. Spin rate comes mostly from arm speed and how the ball rolls off the fingertips at release.
Spin matters because a spinning ball drags air to one side, and the air pushes the ball the other way. This is called the Magnus effect. Backspin on a fastball fights gravity, so the pitch drops less than hitters expect. Topspin on a curveball adds to gravity, so it drops more. Sidespin moves the ball left or right. The more useful spin a pitch has, the bigger that push.
Spin rate counts every rotation, including gyro spin. Gyro spin turns the ball like a football spiral and adds little movement. That's why PitchLab also reports active spin and spin efficiency. Spin also rises with velocity, so compare pitchers at similar speeds. A quick check is spin rate divided by velocity. MLB four-seam fastballs average about 25 rpm per mph.
Video explanation
Jake Fishman, PitchLab’s co-founder and CEO, pitched in the major leagues for the Miami Marlins. Here he explains spin rate and what it means for your pitching.
What affects spin rate
Arm speed
Spin rises with velocity. A pitcher who adds arm speed usually adds spin at the same time.
Grip and finger pressure
Where the fingers sit on the seams and how firmly they press changes how the ball rolls off the hand. Small grip changes can move spin rate noticeably.
Fingers behind the ball
Fingers that stay behind the ball through release put more force into rotation. When the hand slides around the side of the ball, more of the spin turns into gyro.
Natural hand traits
Finger length, hand size, and the way the ball leaves the fingertips all play a part. This is one reason spin rate is harder to train than spin direction.
Ball feel and conditions
A dry, slick ball or cold hands make it harder to grip and spin the ball. Legal aids like a rosin bag help the fingers hold on.
Fatigue
Tired pitchers lose arm speed and finger strength. Spin often drops late in an outing along with velocity.
What’s a good spin rate?
| Pitch type | Average | Good | Great | Excellent |
|---|---|---|---|---|
| Four-seam fastball | 2,320 | 2,450 | 2,550 | 2,650+ |
| Sinker / two-seamDepends on pitch shape | 2,150 | 2,250 | 2,350 | 2,450+ |
| Slider | 2,450 | 2,550 | 2,650 | 2,750+ |
| Curveball | 2,550 | 2,700 | 2,850 | 3,000+ |
| ChangeupLower is better | 1,750 | 1,600 | 1,450 | ≤1,300 |
| SplitterLower is better | 1,300 | 1,150 | 1,000 | ≤850 |
Figures are for MLB pitchers. College averages run a few hundred rpm lower, and high school lower still. Changeups and splitters work better with less spin because it helps them drop. Sinker spin depends on the shape, since a sinker gets its run and sink from spin direction as much as rpm.
How PitchLab measures it
PitchLab measures spin rate on every pitch from an iPhone on a tripod set about 2 ft behind the pitcher. Each pitch shows spin rate in rpm next to active spin, spin efficiency, and spin axis, so you can see how much of that spin is working.
Spin rate FAQs
How do you measure spin rate 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 measures spin rate in rpm on every pitch from the video, with no sensor or smart ball.
Is there an app that measures spin rate?
Yes. PitchLab measures spin rate with just an iPhone, along with active spin, spin efficiency, and spin axis on every pitch. PitchLab is free to start.
What’s the best app for improving spin rate?
The most useful app shows spin rate on every throw next to the video, so you can test a grip or release change and see the result right away. PitchLab does this with an iPhone and saves every session so you can track spin over time.
What is a good spin rate for a 14-year-old?
Most 14-year-old baseball pitchers spin their fastball somewhere around 1,400 to 1,800 rpm. Spin rises with velocity, so harder throwers usually spin the ball more. A better check is spin divided by velocity. A 14-year-old throwing 65 mph with 1,600 rpm is right around 25 rpm per mph, in line with the MLB average ratio.
Is higher spin rate always better?
No. More spin helps four-seam fastballs, curveballs, and sweepers because it adds ride or break. Changeups and splitters work better with less spin, which lets them drop. Spin only moves the ball when it's active spin, so a high number with a lot of gyro spin may not do much.
How do you increase spin rate?
The most reliable way is to throw harder, since spin rises with velocity. Grip changes, firmer fingertip pressure, and keeping the fingers behind the ball at release can add some spin. Many pitchers gain more from raising spin efficiency than from raw rpm. Track each change so you know what helped.
How does PitchLab measure spin rate?
PitchLab turns an iPhone on a tripod into a pitch tracker. Set the phone about 2 ft behind the pitcher, facing home plate, and it reports spin rate in rpm on every pitch. It also shows active spin, spin efficiency, and spin axis, and tracks trends across sessions.
