Finance
Marginal Cost Calculator
Calculate marginal cost from change in total cost and quantity. Solve for any variable in the MC = ΔCost / ΔQty formula.
Enter values above to calculate
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Marginal Cost Formula
MC = ΔTotal Cost / ΔQuantity
Where ΔTotal Cost is the change in total cost between two production levels and ΔQuantity is the change in units produced.
Rearranged: ΔCost = MC × ΔQty or ΔQty = ΔCost / MC
How to Use This Calculator
Select which value you want to find, then enter the other two. Use this to evaluate pricing strategies, identify production thresholds, or study cost behaviour.
Frequently asked questions
What is marginal cost?
Marginal cost is the additional cost of producing one more unit of output. It equals the change in total cost divided by the change in quantity produced.
How is marginal cost different from average cost?
Average cost is total cost divided by total units produced. Marginal cost is the cost of the next unit only. When marginal cost is below average cost, average cost falls; when above, average cost rises.
When does a firm maximise profit?
A profit-maximising firm produces where marginal cost equals marginal revenue (MC = MR). Producing beyond this point adds more cost than revenue, reducing profit.
What causes marginal cost to rise?
Diminishing returns — as more inputs are added to a fixed factor (like a factory), each additional unit of input yields less extra output, so the cost per extra unit rises.
What is a real-world example of marginal cost?
A bakery producing 100 loaves costs $300 in total. Producing 101 loaves costs $302.50. The marginal cost of the 101st loaf is $2.50.