Fixed costs such as rent, salaries and insurance do not change with output, so spreading them over more units lowers the fixed cost per unit – the basis of economies of scale. AFC falls continuously as quantity rises but never reaches zero.
How to use the Average Fixed Cost Calculator
- Total fixed cost
- Units produced
- Average variable cost per unit
Results update as you type, and every field accepts the units shown in its menu.
How it works
Enter total fixed costs and the number of units, and optionally the variable cost per unit.
Tips
- Use figures for the same period (a month, a quarter or a year) for every input so ratios compare like with like.
- Track the metric over time – the trend usually tells you more than a single value.
- Compare your result with industry benchmarks, which vary a lot between sectors.
- Treat the result as a starting point for a decision, then check the assumptions behind each input.
Common mistakes to avoid
- Mixing monthly and yearly numbers in the same calculation.
- Using revenue where the formula needs profit (or the other way round).
- Forgetting hidden costs such as taxes, fees, overheads or your own time.
Inputs explained
| Field | What to enter |
|---|---|
| Total fixed cost | Amount in your currency |
| Units produced | A number |
| Average variable cost per unit | Amount in your currency |
What each result means
- Average fixed cost = [Total fixed cost]÷[Units produced]
- Average total cost = [Average fixed cost] + [Average variable cost per unit]
- AFC if output doubled = [Total fixed cost]÷(2×[Units produced])
Example values
How the main result changes when Total fixed cost changes and everything else stays at the example values above:
| Total fixed cost | Average fixed cost |
|---|---|
| 10,000 | 2 |
| 15,000 | 3 |
| 20,000 | 4 |
| 25,000 | 5 |
| 30,000 | 6 |
| 40,000 | 8 |
Formula
AFC = total fixed cost ÷ quantityAverage total cost = AFC + average variable costWorked example
Inputs — Total fixed cost: $20,000; Units produced: 5,000; Average variable cost per unit: $3.
Results — Average fixed cost = $4.00; Average total cost = $7.00; AFC if output doubled = $2.00.
Frequently asked questions
Why does average fixed cost fall?
The same fixed cost is shared by more units as output grows.
Can AFC be zero?
No – it approaches zero but never reaches it.
What is the difference between AFC and AVC?
AFC spreads fixed costs; AVC spreads variable costs like materials.
What formula does the Average Fixed Cost Calculator use?
AFC = total fixed cost ÷ quantity.