An isoquant (derived from quantity and the Greek word iso, meaning equal), in microeconomics, is a contour line drawn through the set of points at which the same quantity of output is produced while changing the quantities of two or more inputs. The x and y axis on an isoquant represent two relevant inputs, which are usually a factor of production such as labour, capital, land, or organisation. An isoquant may also be known as an “Iso-Product Curve”, or an “Equal Product Curve”. Isoquant vs. Indifference Curve While an indifference curve mapping helps to solve the utility-maximizing problem of consumers, the isoquant mapping deals with the cost-minimization and profit and output maximisation problem of producers. Indifference curves further differ to isoquants, in that they cannot offer a precise measurement of utility, only how it is relevant to a baseline. Whereas, from an isoquant, the product can be measured accurately in physical units, and it is known by exactly how much isoquant 1 exceeds isoquant 2. Nature and Practical Use of an Isoquant In managerial economics, isoquants are typically drawn along with isocost curves in capital-labor graphs, showing the technological tradeoff between capital and labor in the production function, and the decreasing marginal returns of both inputs. In managerial economics, the unit of isoquant is commonly the net of capital cost. As such, isoquants by nature are downward sloping due to operation of diminishing marginal rates of technical substitution (MRTS). The slope of an isoquant represents the rate at which input x can be substituted for input y. This concept is the MRTS, so MRTS=slope of the isoquant. Thus, the steeper the isoquant, the higher the MRTS. Since MRTS must diminish, isoquants must be convex to their origin. Adding one input while holding the other constant eventually leads to decreasing marginal output. The contour line of an isoquant represents every combination of two inputs which fully maximise a firms’ use of resources (such as budget, or time). Full maximisation of resources is usually considered ‘efficient’. Efficient allocation of factors of production occur only when two isoquants are tangent to one another. If a firm produces to the left of the contour line, then the firm is considered to be operating inefficiently, because they are not maximising use of their available resources. A firm cannot produce to the right of the contour line unless they exceed their constraints. A family of isoquants