— Everyday Math
Loss Percentage Calculator
Calculate loss when something sells for less than it cost. Enter cost and selling price to see the loss percentage, money lost, breakeven price, and whether the percentage is measured on cost or on sale price.
Loss (% of cost)
20%
- Loss
- $20
- Loss as % of cost
- 20%
- Loss as % of sale price
- 25%
- Breakeven price
- $100
— How it works
Loss = cost − selling price. Loss % = loss ÷ base × 100, where the base is the cost (the default) or the sale price. Breakeven price = cost — sell at or above it and there is no loss.
Loss as a percentage
A loss is just a negative profit: when the selling price falls below the cost, the difference is the loss. As a percentage it is normally measured against the cost — how much of what you paid you failed to recover. Buy for 100 and sell for 80, and the 20 loss is a 20% loss on cost. As with profit, the base matters: the same 20 loss is 25% of the 80 sale price, a larger figure because the sale price is the smaller number. The calculator shows both, with cost as the default.
Worked example — cost $100, sold for $80: Loss = $100 − $80 = $20. That is $20 ÷ $100 = 20% of cost, or $20 ÷ $80 = 25% of the sale price. Breakeven was $100.
The breakeven price
The price at which a loss becomes no loss is simply the cost — sell at cost and you recover exactly what you paid, for a 0% result; sell above it and you move into profit. That breakeven figure is the useful target when you are deciding how far you can discount: a clearance price below cost is a deliberate loss, and the calculator shows both how big that loss is and the price you’d need to escape it. Selling below breakeven is sometimes rational — clearing stock, a loss-leader to draw customers — but it should be a choice, not an accident.
Loss % and profit % are the same calculation
Profit percentage and loss percentage are two faces of one formula: the difference between price and cost, over a base, as a percentage. When the price is above cost it is a profit; when it is below, a loss. This calculator is the loss-side framing — if you enter a selling price above the cost it will tell you there is no loss and point you to the profit calculator instead. The arithmetic never changes; only the sign of (price − cost) does.
— Reader questions
How do I calculate loss percentage?
Subtract the selling price from the cost to get the loss, divide by the cost, and multiply by 100. Buying at $100 and selling at $80 gives ($100 − $80) ÷ $100 × 100 = 20% loss. Enter the cost and selling price and the calculator does it instantly.
Is loss percentage measured on cost or on the selling price?
Usually on the cost — how much of what you paid you did not recover — and that is the default here. It can also be measured against the sale price, which gives a larger figure. The calculator shows both so the basis is clear.
What is the breakeven price?
It is the price at which there is neither profit nor loss — exactly the cost. Sell below it and you make a loss; sell at or above it and you do not. The calculator shows the breakeven price alongside the loss.
What if the selling price is above the cost?
Then there is no loss — it is a profit. The calculator will say so and show the gain; use the Profit Percentage calculator to express it as a percentage.
Is loss percentage just negative profit percentage?
Yes. Profit and loss percentage come from the same formula — (price − cost) ÷ base — and differ only in the sign. This calculator frames the result as a positive loss when the price is below cost.