A clear definition

Fixed cost

A fixed cost does not change directly with each additional unit of activity within the period and operating range being considered.

What it means in practice

Rent may remain the same whether a business sells one more item or not. That does not make it permanently unchangeable. Moving premises or increasing capacity can create a new cost level. Define the period and relevant range before modelling. A cost can also contain fixed and variable parts. Separating those parts helps explain what changes with an additional sale and what the business must cover regardless. Fixed describes behaviour within a defined range and period, rather than a cost that can never change. A larger operation may require another premises or supervisor, creating a step in the cost base. Review whether the proposed activity stays within the existing capacity. A break even calculation using current fixed cost can become misleading if growth triggers an additional commitment.

A fictional worked example

A fictional workshop pays ₦300,000 monthly rent within its current capacity, whether it completes 80 jobs or 90.

A useful question

Which cost stays the same for one more order but changes at a larger scale?

Read the practical guide