Quick answer
Break-even happens when total contribution equals fixed cost.
Break-even units = fixed costs / (selling price - variable cost)
The trap is treating that result as a full business decision when it is really just one checkpoint inside a wider model.
What break-even is good at
- testing whether the current contribution per unit is strong enough
- showing whether the sales target is plausible at all
- comparing how price or cost changes move the required volume
What break-even is bad at
- capturing payment timing and working-capital pressure
- showing whether the first production run can be financed
- including channel fees, returns, or route-to-market complexity unless those are already in variable cost
Recover GBP65,000 of fixed cost with a GBP49 sale price and GBP22 of variable cost. Contribution per unit is GBP27, so break-even arrives at roughly 2,408 units. If variable cost rises to GBP25, break-even jumps to roughly 2,708 units.
Practical rule:
if small changes in cost or price move the break-even point dramatically, the business model probably needs more margin headroom.
Use break-even in the right order
- estimate product cost bottom-up
- check break-even volume
- model cashflow and route-to-market pressure