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Break-Even Calculator

Computes the contribution margin per unit and the number of units and revenue required for total revenue to equal total costs (or to reach a target profit).

When to use

You are planning a product, service or event and need to know how many units must be sold at a given price to cover fixed costs, or to earn a specific profit.

Do not use when: Price or variable cost changes with volume (needs a stepwise or non-linear model), or you only need margin/markup on one unit (use margin-markup).

Formula

contribution_margin = price_per_unit − variable_cost_per_unit; break_even_units = (fixed_costs + target_profit) / contribution_margin; break_even_revenue = break_even_units × price_per_unit

Linear cost-volume-profit model: constant price and variable cost per unit, fixed costs constant over the relevant range, single product.

Inputs

Parameter	Type	Required	Description
`fixed_costs`	number	yes	Total costs that do not change with volume over the period (rent, salaries, equipment). Range: ≥ 0, ≤ 1000000000000
`price_per_unit`	number	yes	Revenue received per unit sold. Range: > 0, ≤ 1000000000
`variable_cost_per_unit`	number	yes	Cost incurred for each unit produced or sold (materials, commissions, shipping). Range: ≥ 0, ≤ 1000000000
`target_profit`	number	default 0	Optional profit to earn on top of covering fixed costs. Range: ≥ 0, ≤ 1000000000000

Outputs

Output	Type	Unit	Description
`contribution_margin_per_unit`	number		price_per_unit − variable_cost_per_unit.
`contribution_margin_ratio_percent`	number	%	contribution margin / price × 100.
`break_even_units`	number	units	(fixed_costs + target_profit) / contribution margin per unit.
`break_even_units_rounded_up`	integer	units	break_even_units rounded up to the next whole unit.
`break_even_revenue`	number		break_even_units × price_per_unit, equivalently (fixed_costs + target_profit) / contribution margin ratio.

Example

10,000 fixed, price 50, variable 30: {"fixed_costs":10000,"price_per_unit":50,"variable_cost_per_unit":30} → {"contribution_margin_per_unit":20,"contribution_margin_ratio_percent":40,"break_even_units":500,"break_even_units_rounded_up":500,"break_even_revenue":25000}

60,000 fixed, price 25, variable 10, target profit 15,000: {"fixed_costs":60000,"price_per_unit":25,"variable_cost_per_unit":10,"target_profit":15000} → {"contribution_margin_per_unit":15,"break_even_units":5000,"break_even_revenue":125000}

GET https://tttkmbb.com/api/v1/calculate/break-even?fixed_costs=10000&price_per_unit=50&variable_cost_per_unit=30

Machine access

API: GET https://tttkmbb.com/api/v1/calculate/break-even (query parameters) or POST with a JSON body {"inputs": {...}}
Schema: https://tttkmbb.com/api/v1/calculators/break-even · Markdown: https://tttkmbb.com/finance/break-even.md · JSON definition: https://tttkmbb.com/finance/break-even.json
MCP: server https://tttkmbb.com/mcp, tool run_calculator with calculator_id="break-even"
OpenAPI operationId: calculate_break_even
Freshness: static. Authentication: none. Rate limit: fair use (see rate limits).

Sources

Investopedia – Break-Even Analysis: Definition and Formula (reference)
Wikipedia – Break-even (economics) (reference)
Wikipedia – Contribution margin (reference)

FAQ

What if the variable cost is higher than the price?

Every sale loses money and no volume can cover fixed costs; the calculator returns an error asking for a higher price or lower unit cost.

Is break-even revenue the same as break-even units times price?

Yes. It can also be computed directly as fixed costs divided by the contribution margin ratio, which is useful when you only know the ratio.

Related calculators

Margin and Markup Calculator — Set the unit price from cost and a target margin.
ROI Calculator — Evaluate the return once the project is profitable.