Timeboxes

Timeboxes are defined for each event in Scrum including the Sprint which is the collection of all the other events. They are designed to provide just enough time to meet all outcomes associated with completing the Sprint. In other words, theoretically there should be little to no need for other meetings relating to the commitment of the scrum team to deliver the Sprint Goal during a sprint producing the increment. Logically, this does not exclude the need for ongoing collaboration about the increment within the Scrum Team or with Key Stakeholders.

Time Utilisation

Typically the combined timeboxes take up ~20% which of course leaves ~80%⁽¹⁾ for the developers to concentrate on delivering the current Sprint Goal as well as other tasks that might crop up - for example BAU or fixing issues. It also frees up time for the Product Owner to carry out their own accountabilities. All timeboxes, with the exception of the Daily Scrum, are relative to the sprint length - that is they expand up to the maximum time for a one month sprint but can shorten in line with shorter sprints.

Footnotes

1. Percentages of time can fluctuate based on the length of a working day - for example if you work a 7 hour day the timeboxes will take a higher percentage of time within a sprint than those who work a 9 hour day. The Scrum timeboxes collectively and coincidentally align with the Pareto Principle (80/20 rule).