Fixed Versus Flexible Budgets

In the previous chapter, "Different Types of Budgets," we looked at how budgets can be categorized by time, function, and flexibility. Now, we are going to zoom in on that last category: flexibility.

Imagine you are hosting a grand wedding reception. You plan for 500 guests and budget ₹5,00,000 for catering, which works out to ₹1,000 per plate. On the day of the event, a massive storm hits, and only 300 guests show up. At the end of the night, the caterer hands you a bill for ₹4,00,000.

If you compare this actual bill (₹4,00,000) to your original budget (₹5,00,000), it looks like you saved ₹1,00,000. You might even feel pretty good about your cost control. But wait—you only fed 300 people. At your planned rate of ₹1,000 per plate, feeding 300 people should have cost exactly ₹3,00,000. By spending ₹4,00,000, you actually overspent by ₹1,00,000 based on the number of guests who actually attended.

This simple story highlights the fatal flaw of comparing actual results against a rigid, unchanging plan. In the business world, this rigid plan is called a Fixed Budget, and the solution to this problem is the Flexible Budget.

Let us break down exactly how these two budgets work, why one fails when reality changes, and how to build a budget that adapts to any situation.

The Fixed Budget: A Rigid Masterplan

A fixed budget is exactly what it sounds like: a budget that remains completely unchanged, regardless of the actual volume of output or level of activity achieved. It is drawn up for one specific, assumed level of production.

When a company creates a fixed budget, management makes a best guess about how many units they will produce and sell in the upcoming year. They calculate all their expected costs—materials, labour, rent, electricity—based on that single, specific number.

Why the Fixed Budget Fails for Cost Control

Fixed budgets are perfectly fine for planning purposes at the beginning of the year. You need a target to aim for, after all. But they become practically useless for cost control and performance evaluation at the end of the month or year if your actual production differs from your planned production.

Why? Because it is fundamentally unfair and illogical to compare the costs of producing 8,000 units against a budget that was built for 10,000 units.

If a factory manager produces 20% fewer units than planned, of course their total raw material costs will be lower than the fixed budget. If upper management looks at the fixed budget and praises the manager for "saving money on materials," they are making a massive mistake. The manager didn't save money through efficiency; they just bought less material because they produced less output.

To truly judge if a manager did a good job controlling costs, you must compare their actual spending against what they should have spent for the actual number of units produced. This requires a budget that can bend and adjust.

The Flexible Budget: The Dynamic Solution

A flexible budget solves the "wedding guest" problem. It is a budget that recognizes the difference between fixed and variable costs, and is designed to change in relation to the actual level of activity achieved.

Instead of saying, "Our budget for materials is ₹1,00,000," a flexible budget says, "Our budget for materials is ₹10 per unit produced."

If you produce 10,000 units, your allowed budget is ₹1,00,000. If you produce 8,000 units, your allowed budget automatically "flexes" down to ₹80,000. If you produce 12,000 units, it flexes up to ₹1,20,000.

By flexing the budget to match the actual output, you create a true apples-to-apples comparison. If the factory makes 8,000 units and spends ₹85,000 on materials, the flexible budget (which allows ₹80,000 for 8,000 units) immediately reveals that the manager overspent by ₹5,000. The fixed budget would have hidden this inefficiency.

The Secret Sauce: Understanding Cost Behavior

You cannot build a flexible budget unless you know exactly how your costs behave when production goes up or down. This is the most crucial step in the entire process.

To build a flexible budget, every single cost in the business must be classified into one of three categories: Fixed, Variable, or Semi-Variable.

1. Fixed Costs

These are costs that do not change in total, regardless of how many units you produce (within a relevant range or normal operating capacity).

• Examples: Factory rent, factory insurance, salary of the factory manager, straight-line depreciation on machinery.
• Behavior: The total cost stays the same, but the fixed cost per unit decreases as you produce more (because you are spreading the same rent over more units).

2. Variable Costs

These are costs that change in direct proportion to the level of production. If production doubles, the total variable cost doubles. If production drops to zero, the variable cost drops to zero.

• Examples: Direct materials (wood for a chair), direct labour (wages paid per chair assembled), sales commissions.
• Behavior: The total cost changes, but the variable cost per unit stays exactly the same.

3. Semi-Variable Costs (Mixed Costs)

These are the tricky ones. They have both a fixed component and a variable component. A portion of the cost must be paid just to keep the doors open, and another portion increases as you produce more.

• Examples: Electricity (you pay a fixed line-rental fee, plus a variable charge per unit of power consumed), telephone bills, maintenance of machinery.
• Behavior: Both the total cost and the per-unit cost change when production levels change.

Splitting Semi-Variable Costs: The High-Low Method

Because a flexible budget requires us to treat fixed and variable costs differently, we cannot leave semi-variable costs lumped together. We must surgically split them into their fixed and variable parts.

How do we do this? The most common and exam-friendly technique is the High-Low Method.

The High-Low method looks at historical data, picks the highest level of activity and the lowest level of activity, and uses the difference between them to figure out the variable cost per unit.

High-Low Method: A Quick Example

Suppose you are trying to split the factory maintenance cost, which is semi-variable. You look at the last few months of data:

• Lowest month (March): 4,000 units produced, Total Maintenance Cost = ₹30,000
• Highest month (August): 8,000 units produced, Total Maintenance Cost = ₹50,000

Step 1 to 3: Find the differences

• Difference in Cost = ₹50,000 - ₹30,000 = ₹20,000
• Difference in Units = 8,000 - 4,000 = 4,000 units

Step 4: Find Variable Cost per Unit

• Variable Cost per unit = ₹20,000 / 4,000 units = ₹5 per unit.

Step 5: Find the Fixed Cost Take the highest month (August). We know total cost was ₹50,000 for 8,000 units.

• Total Variable Cost for August = 8,000 units × ₹5 = ₹40,000.
• If Total Cost is ₹50,000, and the Variable part is ₹40,000, the Fixed part must be ₹10,000.

Now you have successfully split the cost! The maintenance cost formula is: ₹10,000 fixed + ₹5 per unit. You can now use this formula to flex the budget to any level of production.

Step-by-Step: Building a Flexible Budget

Now that we understand cost behavior, building the flexible budget is a straightforward mechanical process.

1. 1Determine the capacity levels: Decide which levels of activity you want to show in the budget (e.g., 60%, 80%, 100% of normal capacity).
2. 2Analyze the costs: Take every expense and classify it as fixed, variable, or semi-variable.
3. 3Split the mixed costs: Use the High-Low method (or information provided) to separate semi-variable costs into fixed and variable portions.
4. 4Calculate Variable Costs: For each capacity level, multiply the variable cost per unit by the number of units at that level.
5. 5Insert Fixed Costs: Write in the total fixed costs. Remember, these totals stay exactly the same across all capacity columns.
6. 6Total it up: Add the fixed and variable costs together to get the total budgeted cost for each level of activity.

Worked Example: The Himalayan Furniture Company

Let us put everything together into a comprehensive numerical example.

The Himalayan Furniture Company manufactures wooden desks. The factory's maximum capacity (100%) is 10,000 desks per year. Management wants you to prepare a flexible budget for 60%, 80%, and 100% capacity levels.

Here is the cost data provided at 100% capacity (10,000 units):

• Direct Materials: ₹400 per unit
• Direct Labour: ₹250 per unit
• Factory Rent: ₹5,00,000 (Fixed)
• Depreciation: ₹2,00,000 (Fixed)
• Power & Electricity: ₹3,00,000 (Semi-variable: 40% Fixed, 60% Variable)

Step 1: Determine the units for each capacity level.

• 100% capacity = 10,000 units
• 80% capacity = 8,000 units
• 60% capacity = 6,000 units

Step 2 & 3: Analyze and split the costs.

• Direct Materials: Purely variable. ₹400 per unit.
• Direct Labour: Purely variable. ₹250 per unit.
• Factory Rent: Purely fixed. ₹5,00,000 in total.
• Depreciation: Purely fixed. ₹2,00,000 in total.
• Power & Electricity: This is semi-variable. Total is ₹3,00,000 at 10,000 units.
• Fixed portion = 40% of ₹3,00,000 = ₹1,20,000. (This will stay constant).
• Variable portion = 60% of ₹3,00,000 = ₹1,80,000.
• Variable cost per unit = ₹1,80,000 / 10,000 units = ₹18 per unit.

Step 4, 5 & 6: Draft the Flexible Budget.

Let's calculate the columns for 6,000 units (60%), 8,000 units (80%), and 10,000 units (100%).

Variable Costs:

• Direct Materials (₹400/unit):
• At 60%: 6,000 × 400 = ₹24,00,000
• At 80%: 8,000 × 400 = ₹32,00,000
• At 100%: 10,000 × 400 = ₹40,00,000
• Direct Labour (₹250/unit):
• At 60%: 6,000 × 250 = ₹15,00,000
• At 80%: 8,000 × 250 = ₹20,00,000
• At 100%: 10,000 × 250 = ₹25,00,000
• Power (Variable portion - ₹18/unit):
• At 60%: 6,000 × 18 = ₹1,08,000
• At 80%: 8,000 × 18 = ₹1,44,000
• At 100%: 10,000 × 18 = ₹1,80,000

Total Variable Costs:

• At 60%: ₹24,00,000 + ₹15,00,000 + ₹1,08,000 = ₹40,08,000
• At 80%: ₹32,00,000 + ₹20,00,000 + ₹1,44,000 = ₹53,44,000
• At 100%: ₹40,00,000 + ₹25,00,000 + ₹1,80,000 = ₹66,80,000

Fixed Costs (Constant across all levels):

• Factory Rent: ₹5,00,000
• Depreciation: ₹2,00,000
• Power (Fixed portion): ₹1,20,000

Total Fixed Costs:

• At 60%: ₹8,20,000
• At 80%: ₹8,20,000
• At 100%: ₹8,20,000

Total Budgeted Cost (Variable + Fixed):

• At 60% Capacity (6,000 units): ₹40,08,000 + ₹8,20,000 = ₹48,28,000
• At 80% Capacity (8,000 units): ₹53,44,000 + ₹8,20,000 = ₹61,64,000
• At 100% Capacity (10,000 units): ₹66,80,000 + ₹8,20,000 = ₹75,00,000

Notice how the total cost scales logically. If the factory ends up producing 8,000 units, management will not compare actual costs to the ₹75,00,000 master plan. They will compare actual costs to the ₹61,64,000 flexible budget. If actual costs are ₹62,00,000, they know they have a ₹36,000 adverse variance to investigate.

Comparing Fixed and Flexible Budgets

To solidify your understanding, let us look at a direct comparison of the two approaches:

• Flexibility: A fixed budget is rigid and remains unchanged regardless of actual volume. A flexible budget is dynamic and adjusts to the actual volume of output achieved.
• Condition of Use: A fixed budget is only useful if the actual level of activity turns out to be exactly the same as the budgeted level of activity (which almost never happens). A flexible budget is useful under any level of activity.
• Cost Classification: A fixed budget does not strictly require costs to be separated into fixed and variable components (though it's good practice). A flexible budget absolutely requires all costs to be classified into fixed, variable, and semi-variable components.
• Performance Evaluation: Comparing actual results to a fixed budget gives misleading variances if output levels differ. Comparing actual results to a flexible budget provides accurate, meaningful variances for true performance evaluation.
• Complexity: A fixed budget is simple and quick to prepare. A flexible budget is more complex and time-consuming because it requires detailed cost behavior analysis.

Quick Revision

• A Fixed Budget is prepared for a single, specific level of activity and does not change if actual output differs.
• Fixed budgets are useless for cost control if actual production doesn't match planned production, because comparing costs at two different volume levels is like comparing apples to oranges.
• A Flexible Budget adjusts its allowed costs based on the actual level of activity achieved.
• The primary purpose of a flexible budget is to enable meaningful variance analysis (comparing actual vs. budgeted costs fairly).
• To build a flexible budget, you must classify all costs as Fixed, Variable, or Semi-Variable.
• Fixed costs remain constant in total, but change per unit.
• Variable costs remain constant per unit, but change in total.
• Semi-variable costs must be split into fixed and variable components, often using the High-Low Method.
• The High-Low method formula for variable cost per unit is: (Difference in Total Cost) ÷ (Difference in Activity Level).
• When drafting the flexible budget, multiply the variable cost per unit by the new activity level, but keep the total fixed costs exactly the same across all columns.