DROPS Calculator

The DROPS Calculator provides a common benchmark in the classification of the potential consequences of a dropped object.

One of a number of similar tools, the DROPS Calculator is endorsed by the DROPS Workgroup and recognised by the majority of Operators and Contractors in the global oil and gas sector. While other ‘calculators’ exist, they all follow the same principle – plotting the mass of a dropped object against the distance it falls to determine its possible consequences.


  • The calculator assumes a blunt object so is not compatible with broken glass, metal shards etc with may puncture the skin and damage tissue/organic functions
  • The wearing of standard PPE, eg hard hat, safety boots and eye protection, is assumed in the calculator
  • There is no requirement to subtract the average height of an individual when determining fall distance. The calculation is based on the object striking solid ground. Remember personnel may be crouched or prone, or objects may strike lower parts of the body
  • DROPS Calculator and other similar tools are guides only providing cursory indication of possible outcome – they are not an accurate prediction
  •  In reality, even a small object falling from height can be lethal. The heavier the object, the more severe the consequences - the further it falls, the more severe the consequences.

The DROPS Calculator is best employed during planning and risk assessment processes. It will determine the potential severity rating of potential dropped object hazards and help with the risk ranking of appropriate corrective actions and control measures.
Electronic versions of the Calculator tool are available here
his Excel File contains a quick tool to calculate the potential consequenses of various drops.

An example of a DROPS graph.  The height of the dropped object vs the mass of je object rated for potential injuries or possible fatality.