Squat counter app: let your camera count every rep
Proof90 counts your squats with your phone's camera, hands-free. On-device pose detection finds your hips, knees and ankles and counts a rep each time you go down and stand back up. The phone doesn't need to be on your body or in your hand. Nothing is recorded, stored or uploaded, and you don't need an account. Below: how the camera decides a rep happened, a 60-second setup, what depth counts, and how to count squats with no app at all.
Get it on theApp StoreGet it onGoogle Play
How the camera decides a squat happened
Most squat counter apps use the phone's motion sensor, so they count the phone moving down and up, in your hand or on your lap. A camera counter watches your body instead. Here is what Proof90 does with each frame.
- It finds your joints on the phone. Apple's Vision framework on iPhone, Google's ML Kit on Android. No video leaves the device.
- It measures the angle at your knee, between your hip, knee and ankle. A straight leg is 180°. An angle, unlike distance moved on screen, doesn't change with how far away or how tall you are.
- It picks the side it can see best. Side-on, your near leg hides the far one. The counter measures the near leg and sticks with it, rather than flicking between legs mid-rep.
- It counts bottom-to-top. Standing is "top". When your knee angle closes past the bottom line you are "down"; when it opens past the top line again, that is one rep. Until it has learned your range, the bottom line is 110° and the top line is 160°.
- It learns your range from your first three reps. After three counted reps it sets your bottom at a quarter of the way up your own range and your top at three quarters, and judges every later rep against those. It will only do this once you have actually got down to 120° or less at the knee, so a shallow bounce can't teach it that shallow is enough.
- It ignores wobble. You have to spend at least a quarter of a second at the bottom, and two reps closer than 0.7 seconds apart are treated as jitter, not athleticism. A trembling hold at the bottom doesn't become a run of extra reps.
- It refuses to guess. Hips, knees, ankles and shoulders all have to be clearly visible before it counts anything. If they aren't, it says "Get your whole body in frame" or "Your hips and legs aren't fully visible" instead of quietly miscounting.
What depth counts
Before the counter has learned your range, a rep needs your knee to bend to 110° or less, then straighten to 160° or more. Once it has seen three real reps, "down" means at least a quarter of the way into your own range and "up" means at least three quarters of the way back out of it. In practice: squat to the depth you can do properly, every rep, and the counter follows you. Drop to a half-squat after it has calibrated to a deep one and the half-squats won't count.
The counter measures range, nothing more. It doesn't judge knee position, back angle, balance or whether a depth is right for you. If squatting hurts your knees, hips or back, or you are coming back from an injury, see a physiotherapist or doctor first; an app that counts cannot tell you whether you should be squatting.
Set your phone up in 60 seconds
- Prop it side-on, at about knee to hip height. Lean it against a wall, a water bottle or a shoe, screen facing you. Side-on is what lets it see the bend at your knee.
- Step back until your head and feet are both in the picture with a hand's width to spare at the top and bottom. Two to three metres is usually enough.
- Put the light in front of you, not behind you. A window or lamp behind the phone is good. A window behind you turns you into a silhouette.
- Wear something that shows your knees and hips. Shorts or fitted leggings are easiest. Long, baggy trousers can hide the knee joint the counter is following.
- Clear the frame. One person, no pets, no mirror reflections in shot.
- Stand still in your starting position until the counter says it can see you, then do your first three reps at full depth. Those three set your range.
Why a rep was missed, and the fix
| What you see | Likely cause | Fix |
|---|---|---|
| Counter never starts | Hips, knees, ankles or shoulders out of shot | Step back, or lower the phone so your feet are in frame |
| First reps aren't counted | Phone propped before you were still in position | Hold the start position until the "in frame" message clears, then begin |
| Some reps miss, some count | Shallow or uneven depth after it calibrated to deeper reps | Squat to the same depth every rep |
| Counts stop mid-set | Light changed, or you drifted out of frame | Check your feet are still in the picture; move a lamp in front of you |
| "Hips and legs aren't fully visible" | Dark lower half of the picture, or baggy trousers | Add light at floor level; wear fitted shorts or leggings |
| Counts while you stand still | Someone walked through the frame | Clear the frame and restart the set |
| Fast reps under-count | Reps closer than 0.7 seconds apart | Slow down slightly; the counter is built for human pace |
When the camera can't count
Sometimes a set can't be counted: the light went, the dog came in, the phone fell over. Proof90 doesn't pretend. You can log that set on your word, and it is recorded and labelled exactly as that, never as a camera-verified set. The two look different everywhere in the app, so a verified set always means the phone saw it. How verification works explains the labels.
How to count squats properly without an app
A phone is convenient, not necessary. Three habits give you a count you can trust with nothing but a wall and your own voice.
Set a tempo and count the cycle, not the movement. Say "down, two, up" and count "one" only as you reach standing. Counting on the way down and the way up is how people end up with 20 "squats" that were 10.
Use a wall or a chair as a depth marker. Face a wall with your toes a hand's width from it; if you lean forward enough to touch it, the rep didn't count. Or put a chair behind you and lightly touch the seat with the back of your thighs each rep without sitting down. Either one gives you the same depth every time, which is the whole problem a counter solves.
Count in sets of ten, out loud. Do ten, mark it, rest, do the next ten: a mark on paper, a finger on the other hand, or a coin moved between pockets. If you lose track mid-set, go back to the last ten you were sure of.
What a squat counter is really for
Counting is the easy part; showing up for 90 days is not. In Proof90's 90-day challenge, squats start at 3 sets of 8 on day 1 and build to 4 sets of 24 by day 90, and a missed day stays missed.
Questions
Is the squat counter free?
The first week is free on Android. On iPhone the annual plan starts with a 7-day free trial. After that Proof90 is a monthly or annual subscription. The price is shown in the app before you buy, and you can cancel any time in your Apple Account or Google Play settings. Camera counting is part of the 90-day program.
Does it count half squats?
Not once it knows your range. The first three full reps set your depth, and later reps have to reach a quarter of the way into that range to count. Squat to the same depth every rep.
Does it check my form?
No. It measures the bend at your knee and nothing else. It can't see whether your knees track over your toes, whether your back is straight, or whether a depth is safe for you. If you have knee, hip or back pain, ask a physiotherapist or doctor, not an app.
Does it record video of me?
No. Camera frames are processed live on your phone and thrown away. Nothing is recorded, saved or uploaded.
Can I hold the phone instead of propping it up?
No. A camera counter has to see your legs, so the phone needs to be propped up a few steps away, side-on. If you want a counter you hold or keep in your pocket, you want a motion-sensor counter instead; the rep counter guide explains the difference and what each gets wrong.
Does it work without internet?
Yes. Counting happens on the phone. A set finished with no signal still counts, and it syncs when you're back online.
Can it count push-ups too?
Yes. Push-ups are counted the same way, from the angle at your elbow with the phone on the floor side-on. See the push-up counter guide.