Relevant Range: Videos & Practice Problems
Relevant Range is the range of activity levels where costs behave the way they are expected to behave. Within a relevant range, fixed costs stay fixed and average variable cost per unit does not change. This idea matters because costs that seem stable can shift once activity moves beyond certain limits.
A key feature of Relevant Range is the presence of a break point, which is the activity level where the cost pattern changes. On a cost graph, one relevant range can show a flat fixed-cost pattern, while another range may jump to a new fixed-cost level or switch to a variable-cost pattern. In other cases, the variable cost per unit can change after the break point, such as when quantity discounts reduce the cost per unit.
Businesses use relevant ranges to recognize that cost behavior is only reliable within specific operating limits. When activity moves outside those limits, fixed costs may no longer remain fixed, and variable cost per unit may shift, creating multiple relevant ranges that must be identified and monitored carefully.
Relevant Range
Relevant Range
AI Megacomputer Co. negotiates a deal with the local utility company to provide them with 1 million kWh per month. Their contract stipulates that if AI Megacomputer Co. uses more than 1 million kWh in a month they will pay a variable rate of \$0.30 per kWh. How many relevant ranges does AI Megacomputer Co. have in measuring their electricity use, and why?
One: A single contract specifies all the business’ costs, so there is only one relevant range.
One: Since the rate is \$0.30 per kWh, it is irrelevant whether they pay for some of this cost in advance.
Two: Since the cost is fixed below 1 million kWh and variable above 1 million kWh there are 2 relevant ranges.
Three: AI Megacomputer Co. has a relevant range when they use no power, another when they use 0-1 million kWh and a third when they use more than 1 million kWh.
Here's what students ask on this topic:
Relevant range is the span of activity levels where cost behavior assumptions hold true. Within this range, fixed costs remain constant, and the average variable cost per unit does not change. This concept is important because in real-world scenarios, costs do not always behave consistently across all levels of production or activity. When a company operates within its relevant range, managers can predict costs accurately. However, if activity moves outside this range, cost behavior may shift, causing fixed costs to increase or variable costs per unit to change. Understanding relevant range helps managers make better budgeting and cost control decisions by recognizing the limits within which cost assumptions are valid.
Within the relevant range, fixed costs remain constant regardless of changes in activity level. For example, a company might pay a fixed amount for a server that can handle up to 1,500 requests per second. As long as requests stay below this limit, the cost is fixed. However, if activity exceeds the relevant range, such as more than 1,500 requests per second, fixed costs can increase abruptly, like needing to buy an additional server. This creates a new relevant range with a higher fixed cost. Therefore, fixed costs are only truly fixed within a specific range of activity, and outside that range, they can change in steps or jumps.
Within the relevant range, the average variable cost per unit remains constant. However, when a company operates outside this range, the variable cost per unit can change. For instance, if a company buys screws, they might pay 3 cents per screw up to 5,000 screws. Beyond that, the price per screw might drop to 2 cents due to bulk discounts. This change in variable cost per unit marks a new relevant range. Thus, variable costs per unit are stable only within a relevant range, and shifts in cost behavior occur when activity levels cross break points.
Yes, a single cost can have multiple relevant ranges. This happens when cost behavior changes at certain activity levels. For example, consider a lawyer on retainer. The company pays a fixed amount for 100 hours of legal work. This is the first relevant range where the cost is fixed. If the company uses more than 100 hours, they must pay additional hours at an hourly rate, making the cost variable. This creates a second relevant range with different cost behavior. Similarly, a server cost is fixed up to 1,500 requests per second but jumps when demand exceeds that, creating multiple relevant ranges for the same cost.
Understanding the relevant range is crucial because it helps managers make accurate cost predictions and informed decisions. Cost assumptions about fixed and variable costs are only valid within the relevant range. If managers ignore this and assume costs behave the same outside the range, they may underestimate expenses or misprice products. Recognizing break points where costs change allows managers to plan for additional resources, adjust budgets, and optimize operations. It also helps in analyzing cost behavior more realistically, leading to better financial control and strategic planning.
