Calculate Haller Index from transverse and anteroposterior chest diameters, plus correction and asymmetry indexes from AP measurements.

Haller Index Calculator

Haller Index
Correction Index
Asymmetry Index

Enter any 2 values to calculate the missing variable

Haller Index Formula

The following formula is used to calculate the Haller Index. 

HI = T / AP

Variables:

  • HI is the Haller Index
  • T is the internal transverse diameter of the chest (inner rib to inner rib) at the level of maximum deformity (mm)
  • AP is the minimum anteroposterior diameter at the same level (distance from the posterior sternum to the anterior spine/vertebral body) (mm)

To calculate the Haller Index, divide the internal transverse diameter (left-to-right) by the minimum anteroposterior (sternum-to-spine) distance at the same level. The result is the Haller Index, a measure of chest wall deformity.

What is a Haller Index?

The Haller Index is a measurement used in radiology (typically on axial chest CT) to help describe the severity of pectus excavatum, a condition where the breastbone sinks into the chest. It is calculated as the internal transverse chest diameter divided by the minimum anteroposterior distance between the sternum and the spine. A typical Haller Index is around 2.0–2.5 (often about 2.5), while an index of 3.25 or higher is commonly used as a severe threshold and may prompt surgical evaluation.

How to Calculate Haller Index?

The following steps outline how to calculate the Haller Index.

  1. First, determine the internal transverse diameter of the chest (T) at the level of maximum deformity (typically measured on CT), in millimeters (mm).
  2. Next, determine the minimum anteroposterior distance from the posterior sternum to the anterior spine/vertebral body (AP) at the same level, in millimeters (mm).
  3. Next, gather the formula from above: HI = T / AP.
  4. Finally, calculate the Haller Index.
  5. After inserting the values of T and AP into the formula and calculating the result, check your answer with the calculator above.

Example Problem:

Use the following variables as an example problem to test your knowledge.

Internal transverse diameter (T) = 250 mm

Minimum anteroposterior distance (AP) = 100 mm