Not all business costs behave the same way.
Some costs stay the same even when sales are slow. Others rise when the business does more work. Understanding the difference helps you budget, price correctly and avoid cash-flow pressure.
If you do not know which costs are fixed and which are variable, you may charge too little, plan too optimistically, or feel surprised when a quiet month still costs almost as much as a busy one.
Why sorting costs matters
Every business spends money to operate. But treating all costs as equal leads to poor decisions.
A caterer may charge for ingredients but forget packaging, transport, electricity, helper wages and wasted stock. The sale looks good, but the profit is too small. A repair business may celebrate a busy month without noticing that rent, insurance and loan repayments stayed the same, and still had to be paid.
Definition
Fixed costs
Fixed costs are business expenses that usually stay the same each month, regardless of how much you sell or produce.
Definition
Variable costs
Variable costs are business expenses that increase or decrease depending on how much you sell, produce or deliver.
Fixed costs: what you pay every month
Fixed costs continue even when sales are low. They are the costs that keep the business running whether you have one customer or ten.
Common fixed costs include rent, salaries, loan repayments, insurance, internet, phone contracts, storage and software subscriptions.
Because fixed costs do not drop in a slow month, they create a floor, a minimum amount the business must earn just to stay open. A business with high fixed costs needs regular income to survive.
A quiet month with the same bills
You run a small salon. January is slow, only half your usual appointments are booked.
But rent, insurance, your phone contract and your assistant's salary are still due in full. Variable costs like hair products and colour are lower because you did less work.
| Fixed costs | Variable costs |
|---|---|
| Stay roughly the same each month | Change with how much you sell or produce |
| Must be paid even in a slow month | Usually lower when sales are slow |
| Examples: rent, salaries, insurance | Examples: stock, materials, fuel, casual labour |
| Create a minimum cost to stay open | Rise when workload increases |
Variable costs: what changes with your workload
Variable costs rise when you do more work and fall when you do less. Stock, raw materials, packaging, fuel for deliveries, casual labour, payment processing fees, production electricity, cleaning supplies and job-specific transport often fall into this group.
When you price a job or product, variable costs are the expenses tied directly to delivering that sale. If your price does not cover them, plus a share of fixed costs, you may be working at a loss without realising it.
Use costs in your decisions
Costs are not just expenses on a list. They are signals that help you make better choices.
Before hiring, moving premises or buying equipment, ask whether the decision adds a new fixed cost. A new employee, a larger shop or a monthly software subscription increases what the business must earn every month, even in quiet periods.
Before accepting a job, ask whether the price covers variable costs and leaves room for profit after fixed costs are considered.
Pricing a job without the full picture
You run a mobile car wash. A fleet client offers R3,500 for a monthly contract covering 20 vehicles.
You calculate water, soap and fuel at R1,200 and accept the job. But you forgot travel time, wear on equipment, casual labour for a second day, and your share of insurance and phone costs.
Sort your costs into three lists
A practical way to understand your cost structure is to sort everything the business spends into three groups.
Once sorted, ask: Which costs are increasing? Which can be reduced? Which help the business earn more? The answers guide pricing, budgeting and spending decisions.
A common mistake
Forgetting fixed costs when comparing a good month to a quiet month.
A busy month may feel profitable because variable costs are covered and cash is flowing. But if fixed costs are high, a quiet month can wipe out that buffer quickly. Always account for standing costs when judging whether the business is truly healthy.
Your next step
Make three lists: monthly fixed costs, variable costs per job or sale, and occasional costs. Add rough amounts to each. This single exercise often reveals where pricing or spending needs attention.
Keep learning
The next topic is plan before you spend.
Once you understand your costs, the spending decisions you make, on equipment, stock, hiring or growth, become easier to judge with confidence.