Fixed vs Variable Costs: Examples and Why They Matter
Fixed vs variable costs explained with examples by industry, a worked contribution margin calculation, a classification checklist and the mistakes to avoid.
Quick answer: Fixed vs variable costs is about how a cost behaves when activity changes. Fixed costs, like rent and insurance, stay the same whether you sell one unit or a thousand. Variable costs, like materials, shipping and payment fees, rise and fall with each sale. Knowing which is which lets you price correctly and find your break-even point.
Every business owner eventually asks the same questions: How many sales do I need just to cover my costs? Can I afford to offer a discount? Should I take this big order at a lower price? The answers all depend on splitting costs into fixed and variable. This guide explains both types, gives examples for common kinds of small business, shows the contribution margin arithmetic with a worked example, and ends with a checklist and the mistakes that most often distort the numbers.
What are fixed costs?
Fixed costs stay constant in total over a period, regardless of sales volume, as long as the business stays within its current capacity. They are the cost of being open for business. Typical examples:
- Rent or lease payments for a shop, office or workshop
- Insurance premiums
- Salaries for staff paid regardless of output
- Flat-rate software subscriptions and phone plans
- Loan repayments and interest on fixed-term debt
- Depreciation on equipment and vehicles
- Accountant, bookkeeper or legal retainers
- Licenses, permits and professional memberships
Because fixed costs do not change with volume, the fixed cost per unit falls as you sell more. $3,000 of monthly rent is $30 per unit if you sell 100 units, but only $10 per unit at 300 units. That is the basic reason volume helps profitability.
What are variable costs?
Variable costs change in direct proportion to activity. If you sell nothing, they are close to zero; sell twice as much and they roughly double. Typical examples:
- Raw materials, ingredients and stock bought for resale
- Packaging and labels
- Shipping and delivery charges
- Card processing and marketplace fees charged as a percentage of each sale
- Sales commissions
- Hourly or piece-rate labor that scales with production
- Subcontractors paid per job
- Fuel and mileage for delivery or site visits
The variable cost per unit stays roughly constant, while the total rises with volume. For product businesses, most variable costs flow into cost of goods sold, though some, such as payment fees and shipping to customers, may be recorded as operating expenses.
Semi-variable (mixed) costs
Many real bills are a mix. An electricity bill may have a fixed daily standing charge plus a usage charge. A salesperson may receive a base salary plus commission. A delivery van has fixed insurance and lease costs plus variable fuel. For analysis, split each mixed cost into its fixed and variable parts rather than forcing it into one bucket.
Step costs
Some fixed costs stay flat until you hit a capacity limit and then jump. A café can serve a certain number of customers with two baristas; beyond that it needs a third. These step costs are fixed within a range but change when you grow past it, which is worth remembering when you plan for expansion.
Fixed vs variable costs: comparison table
| Feature | Fixed costs | Variable costs |
|---|---|---|
| Behavior as volume changes | Total stays the same | Total rises and falls with volume |
| Cost per unit | Falls as volume rises | Stays roughly constant |
| With zero sales | Still payable | Close to zero |
| Examples | Rent, insurance, salaries, subscriptions | Materials, shipping, commissions, payment fees |
| How to reduce | Renegotiate contracts, downsize, share space | Better supplier prices, less waste, efficient processes |
| Risk profile | Higher risk in a downturn | Flexes down with sales |
| Role in analysis | Must be covered by total contribution margin | Subtracted from price to find contribution margin |
| Budgeting | Predictable monthly amount | Forecast from expected sales volume |
Examples by type of business
| Business | Mostly fixed | Mostly variable |
|---|---|---|
| Freelance designer | Software subscriptions, computer depreciation, insurance, coworking desk | Stock images per project, subcontracted work, payment fees |
| Bakery | Lease, oven depreciation, salaried manager | Flour, butter, packaging, hourly bakers' extra shifts |
| Online store | Store platform plan, warehouse rent, salaried staff | Inventory, shipping, packaging, marketplace and card fees |
| Plumbing contractor | Van lease, insurance, licenses, office admin salary | Pipes and fittings, fuel, hourly helpers, disposal fees |
Worked example: contribution margin and break-even
The numbers below are illustrative. A small candle business sells candles at $24 each.
Variable cost per candle
- Wax, wick and fragrance: $5.50
- Jar and label: $2.50
- Packaging: $1.00
- Payment processing (an assumed 3% of $24): $0.72
- Total variable cost: $5.50 + $2.50 + $1.00 + $0.72 = $9.72
Contribution margin per candle
- $24.00 − $9.72 = $14.28
- Contribution margin ratio: $14.28 ÷ $24.00 = 59.5%
Monthly fixed costs
- Studio rent: $1,200
- Insurance: $150
- Website and software: $90
- Equipment depreciation: $60
- Total fixed costs: $1,200 + $150 + $90 + $60 = $1,500
Break-even volume
- $1,500 ÷ $14.28 = 105.04, so the business needs to sell 106 candles a month to cover all costs
Profit at 250 candles
- Total contribution: 250 × $14.28 = $3,570
- Profit before tax: $3,570 − $1,500 = $2,070
Testing a 15% discount
- New price: $24.00 × 0.85 = $20.40
- Payment fee falls to $20.40 × 0.03 = $0.61, so variable cost is $9.00 + $0.61 = $9.61
- New contribution margin: $20.40 − $9.61 = $10.79
- New break-even: $1,500 ÷ $10.79 = 139.02, so 140 candles
A 15% price cut lowers the contribution per candle by about 24% ($14.28 to $10.79) and raises the break-even volume from 106 to 140 candles. That is why separating fixed vs variable costs is so useful before you run a sale. Our full guide to the break-even point covers the formula in sales-dollar terms as well.
Why fixed vs variable costs matter
Pricing
Your price must cover variable cost per unit plus a share of fixed costs plus profit. Our guide on how to price a product builds on exactly this split. For service work, the same logic applies to hourly rates: your rate has to cover the direct cost of each hour plus your overhead.
Budgeting and cash planning
Fixed costs give you a baseline you must fund every month. Variable costs can be forecast from expected sales. Put both into your small business budget and your cash flow forecast so a slow month does not catch you out.
Operating leverage and risk
A business with high fixed costs and low variable costs, like a gym or software company, earns a lot from each extra sale once fixed costs are covered, but suffers more when sales fall. A business with mostly variable costs is more flexible but earns less from each extra unit. Neither is better; knowing your mix tells you how much risk you carry.
Capital purchases
Buying equipment usually adds fixed costs through depreciation and financing. Whether a purchase is treated as a capital item or a running expense affects how it shows up; see CapEx vs OpEx for that distinction.
Fixed vs variable costs for service businesses
Service businesses often assume the split only matters for companies that make products, but it is just as useful when you sell time. For a consultant, agency or trades business, the unit is usually a billable hour or a job rather than a physical item.
Variable costs per job might include subcontractor hours, travel, materials passed through to the client and payment processing fees. Fixed costs are everything you pay whether or not a client books you: insurance, software, phone, vehicle lease, office space and your own baseline salary. Divide monthly fixed costs by the number of hours you can realistically bill, not the hours you work, and you get the overhead each billable hour has to carry. Add the variable cost of the job and a profit margin, and you have a defensible rate.
This view also explains why quiet months hurt service businesses so much. When bookings drop, variable costs fall with them, but fixed costs keep arriving. Building a cash reserve equal to a few months of fixed costs is a common way to ride out those dips.
Checklist: classifying your costs
- Export the last three to six months of expenses from your books or bank
- For each category, ask: would this change if sales doubled or halved?
- Label each as fixed, variable or mixed
- Split mixed costs into a fixed base and a variable rate
- Calculate variable cost per unit (or per billable hour, or as a percentage of sales)
- Total monthly fixed costs
- Calculate contribution margin per unit and break-even volume
- Review the split each quarter, and whenever you change suppliers, staffing or premises
Accurate categories start with recording every expense consistently; our guide on tracking business expenses covers simple systems that work.
Common mistakes
Treating fixed cost per unit as constant
Dividing last month's rent by last month's units and using that figure for every quote will overprice in busy months and underprice in quiet ones. Keep fixed costs as a monthly total.
Forgetting percentage-based fees
Payment processing, platform and marketplace fees are variable costs that are easy to miss. They can take a meaningful bite out of thin margins.
Ignoring step changes
Planning growth on the assumption that fixed costs will not move ignores the next hire, the bigger lease or the second van.
Leaving the owner's time out
If you do the work yourself, your own time is a real cost. Include a reasonable owner salary as a fixed cost when you calculate break-even, or the numbers will look better than they are.
Discounting without recalculating
As the worked example showed, a modest discount can raise break-even volume sharply. Run the numbers before announcing a sale.
Putting it into practice
Sorting fixed vs variable costs takes an afternoon the first time and a few minutes each quarter after that. Once your prices reflect both cost types, make sure every sale is actually billed. The free invoice generator creates a PDF invoice in your browser for each job or order. It does not track costs or calculate margins, so keep your cost classification in a spreadsheet or bookkeeping tool. For more on budgets, margins and cash, browse the business finance articles, and the SBA's guide to calculating startup costs is a helpful companion if you are estimating fixed costs for a new business.
Frequently asked questions
What is the difference between fixed and variable costs?
Fixed costs stay the same in total regardless of how much you sell or produce within a normal range, such as rent, insurance and salaried staff. Variable costs rise and fall in direct proportion to activity, such as raw materials, packaging, shipping and payment processing fees. Fixed costs are paid even in a month with zero sales; variable costs largely disappear when activity stops.
What are examples of fixed costs?
Common fixed costs include rent or lease payments, business insurance, salaries for staff who are paid regardless of volume, loan repayments, software subscriptions billed at a flat rate, accounting and legal retainers, depreciation on equipment, and license or membership fees. These amounts do not change when you take on one more order, though they can change over time through renegotiation or growth.
What are examples of variable costs?
Typical variable costs are raw materials and inventory, packaging, shipping and delivery charges, sales commissions, card and payment processing fees, piece-rate or hourly labor tied to production, subcontractor costs per job, and usage-based charges such as fuel for deliveries. Each one increases when you sell or produce more and decreases when you sell or produce less.
What is a semi-variable cost?
A semi-variable, or mixed, cost has a fixed portion and a variable portion. A utility bill with a fixed monthly service charge plus a charge per unit of usage is the classic example. A phone plan with a base fee and overage charges, or staff with a base salary plus overtime, are others. For analysis, split each mixed cost into its fixed and variable parts.
Is labor a fixed or variable cost?
It depends on how people are paid. Salaried employees who are paid the same regardless of output are usually treated as a fixed cost. Hourly staff whose hours rise and fall with demand, piece-rate workers and per-job subcontractors behave more like variable costs. Overtime is variable. Many businesses have a mix, so look at how the cost actually behaves rather than the job title.
Is marketing a fixed or variable cost?
Marketing can be either. A flat monthly retainer to an agency or a fixed advertising budget is effectively fixed for the period. Pay-per-click advertising, affiliate commissions and marketplace fees that scale with sales are variable. Because marketing is discretionary, some analysts call it a discretionary fixed cost: you decide the amount in advance, and it does not automatically change with volume.
Why do fixed and variable costs matter for pricing?
Your price must at least cover the variable cost of each unit, or every sale loses money. The amount left over after variable costs, called contribution margin, then has to cover fixed costs before you make any profit. Knowing both lets you calculate a break-even point, judge whether a discount still makes sense, and decide whether a large order at a lower price is worth taking.
Are fixed costs ever really fixed?
Only within a relevant range of activity and a limited time period. If you double output, you may need a bigger workshop or another salaried manager, so fixed costs step up. Over a long enough period, leases end and contracts can be renegotiated. In practice, fixed means fixed for the current period and current capacity, which is enough for monthly budgeting and break-even analysis.
Invoice Creator Editorial Team
Guides on invoicing, cash flow and small-business finance from Invoice Creator, operated by Next Software Development Company. Content is reviewed for accuracy against the fields our own invoice generator produces.
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