A comptroller, also called controller, is a senior financial officer in an organization. Her job is to maintain and audit all financial transactions and records. Comptrollers are very important in any organization–as an organization grows, keeping track of expenditures becomes harder. Having no one to oversee such matters can lead to disastrous consequences.
Comptrollers are usually given only two responsibilities. One is to keep an eye on cash flow. The other is to monitor auditing statements. Keeping track of cash flow is a very tedious and labor-intensive job. It takes dedicated personnel just to make sure that inflow always exceeds outflow. This alone is time consuming enough. Add to that the auditing responsibilities and a comptroller has her hands full.
Governments also have comptrollers. They are usually called public comptrollers. Public comptrollers audit the expenditures of various government agencies. In some countries, like Colombia, the office of the Comptroller General also evaluates and recommends where and how public funds and resources should be allocated.
The United Kingdom is unique when it comes to the use of the word comptroller because they have what is called the “Comptroller of the Household,” an ancient position for a senior member of the Royal household. Nowadays the responsibilities of the Comptroller of the Household are more ceremonial in nature, such as serving as usher during tea parties.