Bowling speed apps explained: speed meter apps, ball trackers and radar guns

Disclosure

Stance Cricket is our product. It is made by CitroSpace, the company founded by the authors of this page, Rishi Gupta and Pradaksh Prasun. Apart from Stance and our calculator, this page describes types of tools in general terms, not any particular product.

Apps of the same type differ in their settings and features, so where we say how a type of tool usually works, check whether yours does the same. We quote no accuracy figure for any app, ours included. The measurement facts here come from the Laws of Cricket, published research and arithmetic shown in the text; the links are under Sources. Tell us if anything is out of date.

Ball speed meters: four ways to measure bowling speed

Live tap timer. You tap once as the ball leaves the hand and again as it reaches the batter, and the app divides the pitch distance by the time between the taps. It is instant, but the time comes from your thumb.

Video frame marking. You film the delivery, step through the clip, and mark the release frame and the arrival frame. The app divides the distance by the number of frames over the frame rate. Many cricket speed meter apps work this way, and our free bowling speed calculator does the same sum in your browser from a frame count you enter.

Automatic video tracking. The app finds the ball in every frame, takes its scale from something of known size, usually the stumps, and works out the speed itself, often alongside line and length or a pitch map. Apps differ in the camera position they ask for. Stance, our web app, is of this type, working on clips you upload in the browser.

Radar. A radar gun measures the ball’s speed directly, from the change in frequency of a signal reflected off it. It needs no distance and no video, but it is a separate device, and it has to be lined up with the ball’s path.

What each method needs, and what limits it

The table describes each type of tool, not any particular app. Features vary between apps of the same type, so check what yours does before you rely on it.

How to use a bowling speed meter app

1. Film the delivery side-on in slow motion (120 or 240 fps), with the phone resting on something solid.
2. Import the clip into the app, or open it in a player that steps one frame at a time.
3. Mark the frame where the ball leaves the hand.
4. Mark the frame where it reaches the batter’s stumps.
5. Check what distance the app assumes. On a full pitch use about 18.5 m, not the 20.12 m between the stumps that some online calculators and apps use by default.
6. Keep the same set-up every time — camera position, frame rate, distance and the moments you mark — and compare each reading only with readings taken the same way.

Speed meter apps: how frame marking works, and what goes wrong

Frame marking is how many speed meter apps work. You import a video, step through it and set two moments: the frame where the ball leaves the hand and the frame where it reaches the batter or the stumps. Some apps show timestamps rather than frame numbers and let you fine-tune each moment; the sum is the same.

Frame rate sets the precision, whichever app you use. Neither release nor arrival falls exactly on a frame, so the true time can be up to about one frame either side of your count. At 30 fps one frame is 33 milliseconds, roughly ±6% on a 120 km/h delivery; at 240 fps it is about 4 milliseconds, under ±1%. Record in slow motion and enter the rate the clip was captured at, not the rate it plays back at. The calculator page has the full table.

Distance is the second source of error, and the one where an app’s default matters. Under Law 6, 20.12 m (22 yards) is the distance between the two sets of stumps; the popping creases are 1.22 m in front of each set (Law 7). No delivery travels the full 20.12 m before reaching the batter, because the ball leaves the hand roughly 1.2–1.8 m in front of the bowler’s stumps. Some online calculators and apps use 20.12 m by default, and a preset labelled 22 yards or 66 ft is the same distance, so check what yours assumes. If the true distance is about 18.5 m, using 20.12 m overstates every reading by about 9%, turning a 120 km/h ball into about 130 km/h.

The third is judgement. Motion blur makes the release frame a matter of opinion, and the arrival frame depends on whether you count to the bat, the stumps or the bounce. Choose the same moments every time and match the distance to them. And any frame count gives the average speed over the ball’s path, which reads lower than the release speed a radar reports, because the ball slows in the air and at the bounce.

Tap timers: the quickest and least precise

Several speed meter apps offer a quick-tap mode, and some are built around tapping. You tap at release and again at arrival, and the app divides the distance by the interval.

The difficulty is how short that interval is. A 120 km/h ball covers 18.5 m in about 0.555 seconds, so small timing errors become large percentages. If your two taps are out by a combined 0.05 seconds — a twentieth of a second — the reading lands anywhere between about 110 and 132 km/h. One frame of 240 fps video, by comparison, is about 0.004 seconds.

Tapping is fine for a rough idea in a game of gully cricket. For a figure you want to track over a season, mark frames on slow-motion video instead, or use one of the automatic methods below.

Automatic tracking apps: speed as part of the picture

Automatic tracking apps find the ball themselves and report its speed alongside where it went. Depending on the app, that can include line and length, a pitch map, swing, spin or the release point. They need a fixed camera and a reference of known size, usually the stumps in view, and they usually ask for a tripod in a set position.

Camera position matters too. A single camera measures movement across the frame well and movement towards or away from the lens poorly, because the image barely changes in that direction. A view from behind the stumps sees the ball’s line and sideways movement clearly; a side-on view sees its progress down the pitch, which is what speed and length are made of. Each position trades one for the other, so check where your app asks you to stand and keep to it every session.

Light and frame rate matter as well. In poor light the camera lengthens the exposure and the ball smears into a streak with no definite position, and at 30 fps a 120 km/h ball moves about 1.1 m between frames.

Radar guns: how they measure and how to line one up

A radar gun measures speed directly, so there is no distance to assume and nothing to mark. But it measures only the part of the ball’s speed along its own line of sight. The shortfall is called the cosine effect: the reading is the true speed multiplied by the cosine of the angle between the gun’s line and the ball’s path. Straight in line, the reading is exact; 10 degrees off, it is about 1.5% low (the cosine of 10° is 0.985); 20 degrees off, about 6% low (the cosine of 20° is 0.940). So stand behind the bowler or behind the stumps, in line with the ball. In one cricket study the radar stood 30 m behind the bowling crease, in line with middle stump, 1.5 m off the ground.

Even lined up, radar has a tolerance. That study quotes ±3% for its radar, about ±3.6 km/h at the average speed it recorded (33 m/s, about 119 km/h). Radar also reads the speed at or just after release, when the ball is fastest, so it will read higher than a frame count of the same ball, which averages the speed over the whole path.

Stance vs other bowling speed apps

Stance is a cricket video analysis web app, and ball speed is one of the things it measures. Below, each thing Stance does is matched to the kind of tool it differs from. For any other app, check whether yours does the same.

Compared with tap timers and frame-marking apps: no distance to set and no frames to mark. Stance finds the ball and the stumps in each frame of an uploaded clip and takes its scale from the stumps, which Law 8 fixes at 71.12 cm tall and 22.86 cm wide, so the 20.12 m problem above does not arise. Because the ball is tracked through the delivery, the same clip gives its speed, the line and length it pitched on, and any movement in flight. Automatic tracking apps work in a similar way, and the same physics applies to all of them: frame rate sets the precision and camera angle sets what can be measured.

Compared with a speed figure on its own: the bowler as well as the ball. Speed tells you how fast; the action tells you why. Stance gives three separate analyses from phone video — batting body mechanics; ball speed, line and length; and run-up and delivery-stride mechanics — plus the elbow angle through the release window for bowlers, as information, not an official ruling. Depending on the app, a tracker may report the release point or arm angle, so check what yours measures of the bowler’s body. Our guide on how to increase bowling speed sets out what the research links to pace.

Compared with single readings: sessions and squads. A session is two or more deliveries analysed together, because one ball is an anecdote, and sessions stack over time so trends show. Coaches get a squad grid with every player measured the same way, and a history that survives changes of staff.

Nothing to install, and the method in the open. Stance runs in the browser: you film with your phone’s own camera and upload the clip. It needs the stumps in frame and at least two deliveries, and our filming guide shows where to put the phone for each clip. We publish the method and its limits rather than quoting an accuracy figure we have not measured in your conditions. Stance is in closed beta; you can join the waitlist.

Stance is not always the right tool. For an instant rough number, a tap timer is quicker. For a figure now and then, a frame count with our free bowling speed calculator, or a frame-marking app, is enough. For a release speed without video, a radar gun lined up with the ball is the better choice. And Stance works on clips you upload, so it is not built to log every ball of a match; a tracking app built for that will suit you better.

How to choose

For a figure now and then, use a frame-marking app or our free calculator, with slow-motion video filmed side-on and the distance set to about 18.5 m on a full pitch. Avoid live tapping if a few km/h matter to you.

For the speed of every ball in a session, plus where it pitched, use an automatic tracking app, set up exactly where it asks.

To understand why your speed changes, look at the bowler’s action as well as the ball. Stance measures the run-up, delivery stride and elbow angle as well as speed, line and length, and our guide to average bowling speed by age shows what published studies measured at each age.

For a reference figure — testing a squad, or checking an app — use a radar gun lined up behind the bowler, and allow a few per cent of tolerance.

Whatever you use, keep the set-up the same — camera position, frame rate, distance and the moments you mark — and compare each reading only with readings taken the same way. If an app tells you that you bowled close to 160 km/h, look for a set-up error before celebrating.