Is my squat deep enough?
A squat is commonly called 'deep enough' when your hip crease drops below the top of your knee — below parallel, the standard used in powerlifting. Most lifters can't judge this on themselves: under load, almost everyone feels deeper than they are. The reliable ways to know are filming yourself from the side, or letting an app measure the joint angle for you on every rep.
What 'parallel' actually means
Side-on, parallel is when your hip crease is level with the top of your knee; below parallel means the hip crease dips under it. In joint terms that's roughly 100°+ of knee flexion for most builds. Powerlifting federations judge exactly this line, which is why side-on video is the standard evidence.
What the research says depth does
Controlled trials favour training deep: Bloomquist et al. (2013) found deep squats produced greater quad and glute growth than shallow squats; Kubo et al. (2019) found full squats grew the adductors and glutes more than half squats. Strength adaptations are also range-specific — you get strong in the range you train, and deep squats carry over to more of it.
Practically: if your goal is size or honest strength numbers, depth is not a style choice, it's part of the dose.
Why you can't feel it
Fatigue and load shrink range of motion quietly — the classic pattern is a lifter whose first rep is at depth and whose fifth is two inches high, feeling identical. Every coach has watched it; no lifter feels it. That's why the fix is measurement, not more effort.
How to measure it objectively
Option one: film yourself side-on at hip height and check the hip-crease-to-knee line frame by frame — accurate but manual. Option two: let the phone do it live. Spotter tracks your knee angle on every rep and scores its depth the moment you finish, so you know exactly which reps were there and which faded — and your weight only progresses when the depth was real.
Answers
How deep should I squat?
For most goals, to at least parallel — hip crease level with the top of the knee — and ideally just below it. Research links deeper squatting with greater quad, glute and adductor growth, and strength gains are specific to the range you train.
How do I check my squat depth without a coach?
Film yourself side-on at hip height, or use an app that measures it live. Spotter reads your knee angle from the camera and scores every rep's depth on-device as you lift.
Is deep squatting bad for your knees?
For healthy lifters with sensible loading, no — deep squats are well tolerated and knee forces are managed by progressive training. If you have an existing knee injury, clear it with a professional first.
Related: AI squat form app · Can an app check my lifting form? · How Spotter works