Joint angle measurer
Drop in a video of a lift, a swing, or a stride and get the joint angles measured frame by frame — knees, hips, and elbows, with the full range each one travelled. Runs entirely in your browser: the video is never uploaded, and there is no account or limit.
About this joint angle checker
This tool finds the body in each frame of your video and measures the angle at each major joint — knees, hips, and elbows. It reports the smallest and largest angle each joint reached, and the range between them, which is usually the number people actually want: how deep the squat went, how far the arm extended, how much the hip closed.
Your video is never uploaded. Pose detection runs inside your browser tab using an on-device model, so nothing is sent to a server at any point. You can check the network tab and see for yourself. That matters more than usual here, because form videos are of your own body.
It measures angles; it does not tell you whether your form is good. What constitutes correct depth or extension depends on your body, your sport, and your goals — that is a conversation with a coach, not a number from a webpage. What this gives you is the measurement to have that conversation with.
Common questions
- Is my video uploaded anywhere?
- No. The pose model runs inside your browser and the video never leaves your device. The only network request is the one-time download of the model file.
- How do I measure squat depth from a video?
- Film from the side with your whole body in frame, then drop the clip here. The left and right knee rows show the minimum angle reached, which is the bottom of the squat. A smaller minimum means a deeper squat.
- What camera angle works best?
- Film perpendicular to the movement, with the entire body visible and reasonably even lighting. Angles are measured in two dimensions, so a joint pointed toward or away from the camera will read short.
- Why did some frames not track?
- The model needs to see the body. Frames where part of you is cut off, badly backlit, or obscured get skipped rather than guessed. The results table shows what percentage of frames each joint was tracked in.
- How long a video can I analyze?
- About a minute. Every second is sampled at ten frames, and a browser tab runs out of memory well before a full training session does. Trim to the rep you care about.
- Can I get the raw numbers?
- Yes. The CSV download gives you every sampled frame with a timestamp and each joint angle, so you can chart it in a spreadsheet or compare sessions.
Tools that support the system
The tool is the starting point. Moonshot is where you carry the work forward.
The tool is the starting point. Moonshot is the software that keeps the issue, next move, and follow-through visible over time.