In economics, the short run is the period of time during which at least one of the factors of production remains fixed in quantity for any given firm - as opposed to the long run.

The actually length of the short run, in terms of calendar time, will vary greatly from industry to industry.

In the short run, firms have some fixed costs while in the long run, all the firm's costs are variable. Even if nothing was produced in the short run, the returns to the fixed factor(s) would still have to be payed e.g. rent paid for office space. Consequently, a firm should continute to produce goods/services in the short run as long as it is covering all its variable costs and some of its fixed costs i.e. the firm is loss minimising.