Relevant Range: Videos & Practice Problems
Relevant Range is the range of activity levels where costs behave the way they are normally expected to behave. Within a relevant range, fixed costs remain fixed and average variable cost per unit stays constant. Once activity moves outside that range, cost behavior can change, so assumptions about fixed and variable costs may no longer hold.
The key to identifying relevant ranges is finding a break point, or the activity level where the cost pattern shifts. A cost may stay fixed up to a capacity limit and then jump to a higher fixed amount, change from fixed to variable, or remain variable while the per-unit rate changes. When a graph shows separate sections where cost is constant or where the slope is constant, each section represents a distinct relevant range.
Understanding cost behavior across relevant ranges helps managers recognize when resource needs, contract terms, or pricing arrangements will change total cost. The main idea is that many costs are only predictable within a certain band of activity, so managers must monitor activity levels as they approach break points.
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 range of activity levels within which the assumptions about cost behavior hold true. Specifically, within this range, fixed costs remain constant, and the variable cost per unit stays the same. Outside this range, costs may change their behavior, such as fixed costs increasing or variable costs per unit shifting. Understanding relevant range helps managers predict costs accurately and make better decisions because costs that appear fixed or variable at one activity level might not behave the same way if production or usage moves beyond this range.
Within the relevant range, fixed costs remain constant regardless of changes in activity level. For example, if a company rents a server that can handle up to 1,500 requests per second, the cost of that server is fixed as long as requests stay below 1,500. However, if activity exceeds this limit, the company may need to buy additional servers, causing fixed costs to increase. Thus, outside the relevant range, fixed costs can jump to a new level, creating a new relevant range with different cost behavior.
Within the relevant range, the variable cost per unit remains constant. For example, if screws cost 3 cents each up to 5,000 units, the cost per screw is stable. However, when purchasing more than 5,000 screws, the price per screw might drop to 2 cents due to bulk discounts. This change in variable cost per unit indicates a new relevant range. Therefore, outside the relevant range, variable costs per unit can increase or decrease, affecting total costs and requiring managers to adjust their cost analysis accordingly.
Yes, a single cost can have multiple relevant ranges. This happens when the cost behavior changes at certain activity levels or breakpoints. For example, a server cost is fixed up to 1,500 requests per second, but if requests exceed that, the company must buy another server, causing a jump in fixed costs and creating a new relevant range. Similarly, a lawyer's retainer fee is fixed up to 100 hours, but beyond that, the cost becomes variable. These breakpoints divide the cost graph into sections, each representing a different relevant range with distinct cost behavior.
Understanding relevant range is crucial because it helps managers predict how costs will behave as activity levels change. If managers assume costs are fixed or variable without considering relevant ranges, they might underestimate or overestimate expenses when production or usage moves beyond typical levels. This can lead to poor budgeting, pricing, and resource allocation decisions. By recognizing relevant ranges and breakpoints, managers can better plan for cost changes, such as when additional equipment or labor is needed, ensuring more accurate financial analysis and strategic planning.
