Consumer surplus is the triangle under the demand curve and above the price. Price ceilings, taxes and monopolies change the surpluses and can create deadweight loss.
How to use the Consumer Surplus Calculator
- Maximum price (demand curve intercept)
- Market (equilibrium) price
- Quantity sold
- Minimum supply price (supply curve intercept)
Results update as you type, and every field accepts the units shown in its menu.
How it works
Enter the maximum price buyers would pay (demand intercept), the market price, the quantity sold and the minimum price sellers accept (supply intercept).
Tips
- Use consistent periods (a year or a quarter) for flow figures and period-end values for balances.
- Average opening and closing balances when a ratio mixes a flow with a stock.
- Benchmark against competitors in the same industry.
- Read the ratio together with others – profitability, liquidity and efficiency tell different stories.
Common mistakes to avoid
- Using sales instead of cost of goods sold for inventory ratios.
- Mixing gross, operating and net profit.
- Ignoring one-off items that distort a single year.
Inputs explained
| Field | What to enter |
|---|---|
| Maximum price (demand curve intercept) | Amount in your currency |
| Market (equilibrium) price | Amount in your currency |
| Quantity sold | A number |
| Minimum supply price (supply curve intercept) | Amount in your currency |
What each result means
- Consumer surplus = 0.5×([Maximum price (demand curve intercept)] – [Market (equilibrium) price])×[Quantity sold]
- Producer surplus = 0.5×([Market (equilibrium) price] – [Minimum supply price (supply curve intercept)])×[Quantity sold]
- Total surplus = [Consumer surplus] + [Producer surplus]
Example values
How the main result changes when Maximum price changes and everything else stays at the example values above:
| Maximum price (demand curve intercept) | Consumer surplus |
|---|---|
| 25 | -2,500 |
| 37.5 | 3,750 |
| 50 | 10,000 |
| 62.5 | 16,250 |
| 75 | 22,500 |
| 100 | 35,000 |
Formula
Consumer surplus = ½ × (maximum price − market price) × quantityProducer surplus = ½ × (market price − minimum supply price) × quantityTotal surplus = consumer + producer surplusWorked example
Inputs — Maximum price (demand curve intercept): $50; Market (equilibrium) price: $30; Quantity sold: 1,000; Minimum supply price (supply curve intercept): $10.
Results — Consumer surplus = $10,000.00; Producer surplus = $10,000.00; Total surplus = $20,000.00.
Frequently asked questions
What is consumer surplus?
The benefit buyers get from paying less than they'd be willing to.
How do taxes affect consumer surplus?
They raise prices and reduce quantity, shrinking surplus.
What is producer surplus?
What sellers receive above their minimum acceptable price.
What formula does the Consumer Surplus Calculator use?
Consumer surplus = ½ × (maximum price − market price) × quantity.