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Over 3M Reps Tracked

What Athletes Are Saying

Glad to see something for weights in the fitness tracker space this has given me all the data I could reasonably ask for, new features roll out continually, etc. Name another wireless VBT option at this price point?
— Oli K

Fair pricing, good people.

Team actively communicates with users, seeks feedback and incorporates requested features regularly. Cool young company that seems to care. I thought the price was more than fair given other options in this space!
— Stella K

Hardware shipped quickly and set up was easy, don't need anything beyond whats in the box so convenient to travel with. Gives me great insights into where I'm at and how and when it's time to level up. I use mainly for powerlifting and tracking my routines.

— Mateo C
Really helps calculate the weight you should be doing at the rate that it should move. It helped me be smarter on the weight that I should add. It improved my performance and will continue to improve in the long run with this product!
— Hector H
It allowed me to increase strength without the risk of any injury as a result I was able to progressively overload. I recommend the product wholeheartedly to any fitness athlete whether a beginner or advanced
— Moe A
Best and most affordable vbt device
— Connor D

A Personal Trainer In Your Pocket

Everything you'd expect from a personal trainer from tracking your reps and rest to planning your workouts to real-time audio feedback.

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The Calibrex App

Our free iOS and Android app is a personal trainer in your pocket:

1. Plans: Choose from dozens of science-backed, carefully curated workouts

2. Live Training: View live data as you train and get real-time feedback

3. Progress Tracking: Review your progress over time and stay accountable to your fitness goals

4. Social Sharing: Share your workouts and insights with friends on your favorite social platforms

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New 🔥


Science proven, professionally curated (and sometimes fun) workouts for all fitness levels. Free on the Calibrex App.
A few examples:

Total Body Barbell Strength

Lower Body Strength

Free Weight Upper Body Focus

Bro Split 1 | Push

Bro Split 2 | Pull

Bro Split 3 | Legs

Full Body Tone

Complete Home Workout

Full Body Machines

Load video: Calibrex 2: What is it?

All of The Tracking, None of The Hassle

Calibrex 2: What Is It?

  • A tiny magnetic sensor snaps onto your wrist, body, and all gym equipment that measures the quantity and quality of your workouts automatically
  • A free app analyses your data and gives you constant feedback, reminders, motivation, and insights on your training
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3 Easy Steps to Train Like A Pro

Load video:

1. Choose a Workout Plan

Pick a world-class workout curated from the best athletes and thought leaders in the world, recommended based on your fitness goals

2. Attach the Calibrex 2

The Calibrex 2 is magnetic so it can seamlessly snap onto any barbell, kettlebell, gym machine or even your body via the Calibrex attachments

Load video:

3. Get liftin'!

We automatically watch your reps, rest, form, and speed and give real-time feedback to make sure you're lifting optimally

Review Your Progress and Results

Review your workouts to see how you are progressing and how you stack up against other Calibrex athletes

Who Is It For?

It's You Vs. You

Eliminate The Intimidation Factor

Ditch Your Gym Notebook

Get Real-Time Audio Cues & Dial In Your Key Lifts

Get Fit In Record Time Using Real Science

Always Know Exactly How You're Performing

Get Automatic Accountability to Your Goals

Use World-Class Workout Plans You Can Actually Trust

Get Shareable Insights Every Workout

Who We Are and Why We're Building This

We're Philip and Nick, an ex European champion 🏸 turned entrepreneur and a nerdy bodybuilder 🏋️ who builds tech products. We came together to create the best personal trainer on earth and make it accessible to everyone.

Our mission is to democratize fitness technology: take all the expensive, gatekept tech and techniques that pro athletes use and give them to everybody. We use the latest in science-backed fitness research and experience of global thought leaders to make getting fit a sure thing.

Our goal at Calibrex is to use the latest technologies to do everything a world-class personal trainer can do but better, cheaper, and faster making your journey to your fitness goals as easy as it can be.

Our Story

Track Every Exercise

Calibrex 2 All Access

What's In the Box:

1. Calibrex 2: The magnetic sensor that clips onto all gym equipment, accurately tracks everything a personal trainer would and more

2. Wrist Band: A convenient wrist attachment for tracking most movements, especially useful for dumbbells

3. Body Clip: Used to track bodyweight movements like pull ups, pushups, and lunges

Hand Assembled in NYC

Ultra Portable

Plug n' Play

Magnetically snaps onto any gym equipment (or your body)

Calibrex 2 - Calibrex
Calibrex 2 - Calibrex



Calibrex 1.0

Philip sketched the first Calibrex device during a math lecture.


A device that helps athletes train smarter.

Origin: Calibration

The Concept

The initial concept:

A pair of devices that can be attached onto both ends of any barbel to detect imbalances in real-time. When the barbell is uneven, the user is notified via sound. Wearing headphones will sound audio on the corresponding side that needs adjustment.

Above is a real demo of the Calibrex 1.0 app and balance feature


Philip 🤝 Nick

Philip started looking around for njneers and caught wind of Nick's success in building over a dozen hardware products from the ground up. Philip slid in Nicks DMs asking for help – Nick politely accepted.

Our Story

Calibrex 1.0

Our first prototype

After a few iterations, Nick builds the first Calibrex Alpha device. Using this first device we were able to start asking coaches and athletes for feedback.

Beta Testing

Beta Testing Calibrex 1.0

We got to work testing both the Calibrex 1.0 hardware and app with high performance coaches around the country.

We had to be smart when selecting the first beta testers as feedback was crucial to improve both our hardware and algorithms at the time.

Hand Assembling Calibrex

Workshop ⚙️

Optimized the workshop to quickly implement improvements based on customer requests and feedback. Started to fulfill growing demand of our hand-built paid beta prototypes.

Using 3D printers, we were able to quickly change plastic dimensions, thickness etc. based on customer feature requests and suggestions, as well as internal stress testing and debugging.


Calibrex 1 Public Beta

After building dozens of units and iterating designs over months, we felt confident enough to launch a public beta.

We knew that having users pay for the experience would accelerate higher quality data and feedback collection. A friend or family member will usually try to protect your feelings.

1M Reps

Just a few months in...

With hundreds of users on the Calibrex 1 platform, we were able to collect over 1M reps in just a few months.

With their help, feature requests and everything that we learned together, we went back to the drawing board. Calibrex 2? 👀


Calibrex 2 Public Beta

In early 2024 we launched the Calibrex 2 Beta, and followed a similar process as the Calibrex 1 to collect detailed feedback and make fast improvements.

As part of the beta program, users get some pretty cool perks:

  • No subz for life
  • Complimentary hardware upcycle
  • Personalized Referral
  • Private Discord Access
  • 1on1 Support on the Calibrex app and web

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Locker Room

Why Basketball Athletes Have Huge Shoulders

Why Basketball Athletes Have Huge Shoulders

Ever notice that basketball players usually have massive shoulders? That’s not because they’re spamming the overhead press machine, but because they spend countless hours with their arms raised above their heads. This sounds just like the point we made in the last paragraph - a lot of time spent under the tension of their own arms.

Read more

Unlocking the Power of Velocity-Based Training (VBT): A Beginner’s Guide with Calibrex

Beginner's Guide To Velocity Based Training

Velocity-Based Training (VBT) is like having a GPS for the gym, similar to how Strava works for runners. VBT devices and apps enable lifters to monitor training volume, velocity, power output and other key metrics just like a GPS helps runners track their exercise pace, volume, distance, etc.

Read more


Please read our FAQs page to find out more.

What is Calibrex?

Calibrex 2 is the first exercise tracker designed for physical exercise.

We've found that most fitness trackers focus mainly on cardiovascular metrics and steps but nothing that can really help us understand our progress in the gym. Calibrex brings technology that currently only pro athletes in pro sports facilities have, in a portable and affordable form factor.

How long does the battery last?

The battery is designed to last about one week or 4 one hour sessions.

Do you have a warranty?

Every Calibrex 2 comes with a Calibrex™️ 1yr warranty.

We back our Calibrex devices with a one year warranty, ensuring that any issues or problems will be promptly resolved.

Are there any subscriptions?

Nope, no subscriptions or fees whatsoever. Just a one time payment to unlock the Calibrex 2, Calibrex app and any new feature that comes out.

What metrics does the Calibrex 2 track?

The Calibrex 2 tracks:

  • Reps/Sets
  • Rep Speed (m/s) & Power (w)
  • Rest Times
  • Speed Loss (Fatigue Monitoring)
  • Calories Burnt

New features are released on the app very often with the help of each Calibrex 2 Beta User™️. Perks include access to feature requesting and early access.