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Hammer Curl Rep Counter

Skip the mental math. Point your phone at yourself and every full-range hammer curl counts itself — sets, reps, and PRs logged while you train your biceps and forearms. Free in your browser today; coming to Google Play and the App Store.

Coming to Google Play & the App Store▶  Try The Rep Counter
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Live screen in miniature — the app’s real hammer curl demo (front view), with the rep counter, form bar, and phase dot. On-device.
Straight From The App

HOW TO DO A PROPER HAMMER CURL

Setup  Stand facing the camera, weights at your sides, palms facing in (thumbs forward).

  1. Curl up keeping your palms facing each other the whole way.
  2. Squeeze at the top, then lower slowly to a full stretch.
  3. Keep your elbows tight to your ribs.
Form cue: Full extension

Same sheet as the ⓘ panel in the app — animated demo included.

How The Counting Works

HANDS-FREE IN THREE STEPS

1

Prop your phone and get in frame

Phone at roughly torso height, stand facing the camera. A quick camera test checks lighting, distance, and angle before you start.

2

The camera locks a 17-point skeleton on you

GOODREPS measures your elbow angle (shoulder → elbow → wrist) on-device — no wearables, no clickers. A pair of dumbbells — palms face each other the whole way.

3

Just work — the counter does the counting

A rep banks at the bottom (~50°) and re-arms near ~155°. Half reps don’t count; after 3 clean reps it calibrates to your range.

Under The Hood

WHAT MAKES A REP COUNT

Form Still Matters

COMMON HAMMER CURL MISTAKES

Swinging the hips

Momentum from the torso steals the work from your brachialis. Brace, then curl — no cheat reps.

Elbows drifting forward

Keep elbows pinned at your sides. If they creep forward you are turning it into a front raise.

Twisting into a regular curl

Palms stay facing each other. Supinating mid-rep changes the exercise.

Cutting the bottom short

Fully straighten at the bottom so every rep starts from a real stretch.

Your Data

PRIVATE BY DESIGN

Rep counting runs entirely on your device — your camera feed is never uploaded.

Pose detection runs in your browser via TensorFlow.js. Camera frames are analyzed in real time and immediately discarded — nothing is recorded, nothing leaves your phone, and we never see them. Sign-in is optional; skip it and everything stays local.

FAQ

QUESTIONS, ANSWERED

Do I need any equipment to check my hammer curl form?

Just your phone for most variations. Add free weights when the pattern is clean — the app still scores the movement either way.

Does it work in a home gym or low light?

Run the built-in camera test first — it checks your lighting, distance, and angle with live green checks before you start. If a rep still slips through, manual counting is always one tap away.

Is my camera feed uploaded anywhere?

No. Pose detection runs entirely on your phone, in your browser. Frames are analyzed in real time and immediately discarded — nothing is recorded, nothing is uploaded.

Keep Going

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Free forever — camera counting for all 60 exercises, no account needed. Pro (voice coaching, programs, depth-camera form checks) is $7/mo, $49/yr, or $99 once. No ads, ever.