Metric captures barbell movements using video analysis and is calibrated by default for 45cm (17.7") circular weight plates. This includes bumper plates, calibrated plates, and cast iron plates.

Metric does not support velocity or bar path tracking for dumbbells, kettlebells, or bodyweight exercises. See Manual entry exercises →

Are all weight plates the same size?

No, weight plates vary in size and type. To accomodate this you may need to set a custom plate diameter in the Metric app before you record velocity.

Customising weight plate size in the Metric app

If you're using non-regulation sized circular plates, you can set a custom diameter before recording to get accurate velocity tracking.

To measure plate diameter: Using a tape measure, ruler or digital measurement app, measure the distance across the plate from edge-to-edge. Metric requires a value in centimetres so multiply your results by 2.54 if working from inches.

Plate size adjustment

To accommodate non-regulation sized circular plates, you can adjust the settings before recording to ensure accurate velocity tracking.

  • Measuring Plate Diameter: Measure the distance across the centre of the weight plate from edge to edge using a tape measure, ruler, or digital measurement tools like the default iOS Measure app. Remember to convert measurements from inches to centimetres (multiply by 2.54).

Enabling custom plate sizes

Changing the default plate size setting is straightforward:

  1. Open the camera to record your next set.
  2. Tap the settings card in the top left corner of the screen.
  3. Toggle on custom plate sizes to override the default 45cm plate size.
  4. Enter your custom plate size in centimetres.

The entered size remains the default unless overridden in subsequent sessions.

For accurate velocity tracking, ensure that plates are at least 10cm in diameter and plates are circular

Understanding weight plate sizes

There are several types of weight plates, found in gyms around the world.

  • Olympic weight plates: These are standardised at 45cm in diameter, designed for use in competitive weightlifting. They provide consistency across training and competitions.
  • Standard Plates: Common in home gyms, these vary more in size and are not regulated by any sports organisations. Standard plates are actually becoming much less standard in gyms around the world as access to Olympic bars and plates and popularity of weightlifting, CrossFit and powerlifting has risen in recent years.
  • Bumper Plates: Made of dense rubber to allow the bar to be dropped from various heights, typically used in Olympic lifting.
  • Technique Plates: Much lighter than standard plates, designed to help beginners practice form without heavy weights.

Understanding the diversity in plate types helps athletes and coaches select the right equipment for their training needs, whether for general fitness, powerlifting, or Olympic-style weightlifting.

What is the difference between standard and Olympic weight plates?

Standard plates have a 2,5cm internal hole for inserting the barbell, which Olympic plates are specially designed to be used on an Olympic barbell with a 50 millimetre (2inch) hole. Olympic weight plates are also a consistent 45cm in diameter where as standard plates — despite the name — do not have standard or consistent sizes.

What size are Olympic weight plates?

Olympic weightlifting plates (also known as calibrated powerlifting plates) 20kg (blue) and 25kg (red) weight plates are uniformly 45cm in diameter, which is critical for ensuring fair competition and effective training at all levels.

Smaller calibrated plate diameter sizes are also standardised:

  • 25kg & 20kg calibrated plates (red & blue): 45cm
  • 15kg calibrated plates (yellow): 35cm
  • 10kg Calibrated Plates (Green): 25cm

Other common plate sizes you will find in gyms:

  • Olympic bumper plates (all weights): 45cm
  • Cast iron plates: 45cm
  • Rubberised 20kg plates with inset grips: 40-42cm

Why are Olympic weight plates so big?

The 45cm diameter of Olympic weight plates, while initially an arbitrary number based on the maximum size of lath technology at the time of their first design serves some key purposes.

  • Plates are designed to ensure that the bar is at a standard height when loaded, which is critical for consistency needed in Olympic weightlifting and powerlifting competition.
  • Larger plates distribute the weight more evenly and increase the bar's stability and reducing stress on the equipment, essential during high-impact drops. This is especially true for bumper plates used in training.
  • The size also allows for the smooth rolling of the bar on the floor, crucial for executing complex lifts with a reduced risk of injury.
  • Facilitates consistent technique: The uniform size helps lifters maintain lifting techniques no matter what gym you are in around the world — keeping height from the ground consistent.
  • Aids safety: The size of plates are big enough to protect the lifter in the case of a dropped snatch or jerk. When the bar falls to the ground the plates are tall enough that the barbell will not hit the head if it were beneath it.