Test your packaging


Use the calculation model in User-friendly Packaging to get an estimate of how many people are able to open different packaging types based on packaging dimensions and the target group’s critical strength. The critical strength is the maximum strength possessed by the target group.


Right you will find calculation models for screw caps, flaps and bags, can with lift ring, can with pull ring and pull of cork. The models have been adjusted in a way that makes it possible to simulate the effect of the end user’s ability to transfer force to packaging types of different dimensions.


Choose calculation model based on type of grip

Not all types of packaging are included in the calculation models. Each company must decide which model will be the best suited for each case. The essential question is what grip is being used in the opening procedure.


The calculation for flaps and bags is included in one model as the same grib is used for both. In order to use this type of calculation model the grip used in the opening procedure has to be a pincer grip. No calculator model has yet been developed for calculating “bag grips”.


See different grips in opening grips >>



Practical examples of packaging analysis

See practical examples of packaging analysis including calculating critical force via the calculation models >>


From these cases you will see that it is not appropriate blindly to trust the model’s results as it will often be a combination of the end user’s physical strength and their cognitive analysis of the packaging – that is their understanding of how the packaging should be opened – which decides how the end user perceives the packaging regarding accessibility.

Calculation models:



Important reservations when using the calculation models

The calculations models are based on a limited amount of data and thus cannot be used as a statistically valid model but more as a guideline and a practical help when choosing dimensions and opening force in order to understand the end user’s strength in relation to the dimensions of the packaging (design and opening grips). The actual critical force has to be calculated via measurements on concrete packaging specimens (mechanical test) and the target group.


Primary data for the calculation models are based on Department of Trade and Industry (DTI), UK´s report: Strength data for design safety phase II, 2002. (See the entire reference list here)