Accuracy on Naiz Fit SizeForm

One of the most common questions we get asked at Naiz Fit is how accurate the recommendation is.

As you know, Naiz Fit SizeForm compares the ideal body shape for a garment with the user's body shape. The answer to the question therefore has two parts: the accuracy in the body measurements, and the accuracy in the garment measurements.

Body measurements

Naiz Fit SizeForm users its own Naiz Brain technology to make all body size estimations.

Naiz Brain can use various types of data to estimate body measurements, including numerical data and images of the user. Naiz Brain combines several mathematical and statistical techniques to obtain highly reliable estimations.


For Naiz Fit SizeForm, the user is asked about their Age, Height, Gender and Weight. This information is used to estimate their body measurements.

With this information, Naiz Fit SizeForm can obtain results with an absolute error which is always below the average jump between sizes. This means we can guarantee that our body size estimation is good enough for making size recommendations.

NaizBrain provides the following measurements to SizeForm for the size recommendations:

  • Chest outline
  • Waist outline
  • Hip outline
  • Body length
  • Thigh outline
  • Leg length

NaizBrain results in the following absolute error values:

Garment measurements

Naiz Fit SizeForm uses four accuracy levels to determine garment measurements:

  • Market Model, applying the average garment measurements for the market in question (Europe, USA, Asia, etc.) for each of the sizes in each type of garment.
  • Standard Model, applying a standard created by an institution or body, such as the EN 13402 standard in Europe.
  • Brand Model, where we register the measurements of common patterns for each brand and type of garment.
  • Product Model, registering the measurements of a specific product.


The system produces a size recommendation for a product based on the maximum available accuracy level. The order of accuracy is the reverse of the above list, i.e. the most accurate is the Product Model and the least accurate is the Market Model.

It's therefore crucial that the brand or online retail business provide our analysts with all the available information.

The accuracy in the size recommendation therefore depends on the level of accuracy provided by the available measurement model.

All brands working with Naiz Fit SizeForm must at least provide garment measurements which enable the system to generate the Brand Model.