Variable cost

Published Friday 24 July 2026

Table of contents

• What is a variable cost?
• Examples of variable costs
• How to calculate variable costs
• Why variable costs matter
• How variable costs differ from fixed costs
• What are stepped costs?
• How variable costs affect pricing and break-even
• Keep on top of your variable costs with Xero
• FAQs on variable costs
• Related terms
• Learn more about variable costs

Key takeaways

• A variable cost is an expense that rises and falls with your business activity, so it climbs when you're busy and drops when you're quiet.
• Common variable costs include inventory, packaging and shipping, payment transaction fees, and sales commissions.
• You work out your total variable cost by multiplying the number of units produced by the variable cost per unit.
• Variable costs move with your output, while fixed costs like rent and insurance stay the same no matter how much you sell.

What is a variable cost?

Variable costs are expenses that go up and down in line with business activity. The busier you are, the higher they go. They're the opposite of fixed costs.

Many variable costs, such as inventory and freight, track your sales closely, because each extra order means more stock to buy and ship. Others, such as marketing and sales travel, still count as variable but don't always match your sales perfectly. Getting a clear picture starts with tracking your business expenses accurately.

Examples of variable costs

Variable costs show up across most parts of a business, and they shift as your workload changes. Here are 7 common examples:

• inventory and raw materials
• packaging and shipping
• transaction fees for card, digital wallet and direct debit payments
• contractors hired during busy times
• marketing
• sales travel
• commissions and referral bonuses

How to calculate variable costs

Working out your variable costs is simple once you know your output and your cost per unit. The basic formula is: total variable cost = number of units produced × variable cost per unit.

Say you make 500 units and each one costs 4 euro in materials and packaging. Your total variable cost is 500 × 4 euro, which comes to 2,000 euro. To find your average variable cost, divide the total variable costs by the number of units, so here it stays at 4 euro per unit.

These figures feed straight into your cost of sales, so accurate numbers keep the rest of your accounts on track.

Why variable costs matter

Variable costs can change from week to week, which makes them harder to budget than fixed costs. That movement is exactly why they're worth watching closely.

When you understand how your variable costs behave, you can set more accurate budgets and plan ahead for business costs as you grow. It also helps you predict your cash flow needs, so you're ready for busy periods without straining your accounts.

How variable costs differ from fixed costs

Every cost your business pays is either variable or fixed. Variable costs move with your activity, while fixed costs stay the same no matter how much you produce or sell.

Fixed costs are the steady expenses you pay whether business is busy or slow. Common examples include:

• rent for your premises
• utilities such as electricity and broadband
• insurance
• permanent wages and salaries

What are stepped costs?

Some costs don't fit neatly into either box, and these are known as stepped or semi-variable costs. They stay flat for a while, then jump up in one big step once you pass a certain level of activity.

Imagine you can make 200 products with your current team. To make another 200, you hire an extra employee, so your wage cost jumps in a single step rather than rising gradually. It then holds steady again until you reach the next limit.

How variable costs affect pricing and break-even

Knowing your variable cost per unit is a big help when you set prices. Each sale needs to cover the variable cost of making it, plus a share of your fixed costs, before you make any profit.

It also helps you find your break-even point, the moment when your sales cover both your fixed and variable costs. Once you know your numbers, you can look for cost saving ideas that lower your variable cost per unit and bring that break-even point closer.

Keep on top of your variable costs with Xero

Xero accounting software brings your costs and cash flow together in one place, so you can see how variable costs shift as your business activity changes. That clear view makes it easier to budget, set prices, and plan for what's next, and you can try it and get one month free.

FAQs on variable costs

Here are answers to some frequently asked questions about variable costs to help you put the term into practice.

Are utilities a fixed or variable cost?

Most everyday utilities like broadband and standing charges are fixed, because you pay a similar amount each month. Usage-based charges, such as electricity that rises with production, can behave as a variable cost.

Is marginal cost the same as a variable cost?

They're closely linked but not identical. Marginal cost is the cost of making 1 more unit, which is usually driven by the variable cost per unit.

How can a business reduce variable costs?

You can negotiate better rates with suppliers, buy materials in bulk, or cut waste in packaging and shipping. Reviewing your payment transaction fees can also lower your costs.

Is advertising a variable cost?

Advertising is usually treated as a variable cost, since you can raise or lower your spend as needed. It doesn't always rise and fall in step with sales, though.

Related terms

• Fixed cost
• Expense
• Operating expense
• Gross profit

Learn more about variable costs

• Overhead costs explained
• Managing petty cash
• Budgeting and forecasting
• Small business accounting