Work expands to fill the time allotted for its completion, regardless of the real amount of work that needs to be done.

It was first published in 1955 by the naval historian C. Northcote Parkinson as an essay in The Economist as a commentary on bureaucracy.

A current form of the law is not the one to which Parkinson referred by that name in the article, but rather a mathematical equation describing the rate at which bureaucracies expand over time.

He explained this growth using two forces:

  1. “An official wants to multiply subordinates, not rivals”, and
  2. “Officials make work for each other.”

Corollaries:

  • If you wait until the last minute, it only takes a minute to do.
  • Berglas’s corollary: no amount of automation will have any significant effect on the size or efficiency of a bureaucracy.

The law can be generalized further as: the demand upon a resource tends to expand to match the supply of the resource (If the price is zero).