Fixed costs are the foundation of your financial vulnerability. Unlike variable costs, which fall when revenue falls, fixed costs continue regardless of trading performance. In a downturn, a business with high fixed costs burns cash faster, breaks even later, and has less flexibility to respond. Understanding, auditing, and systematically reducing your fixed cost base is one of the highest-leverage actions available to a UK SME owner.
This guide covers how to audit your fixed cost base, where the biggest savings typically lie, and how to convert fixed costs to variable where possible.
Fixed costs vs variable costs: a practical definition
A fixed cost stays roughly constant regardless of your revenue level: rent, salaries, loan repayments, insurance, software subscriptions, depreciation. A variable cost rises and falls with revenue: cost of goods sold, delivery costs, transaction fees, commissions.
The distinction matters because your break-even point is determined by your fixed costs. The formula: Break-even revenue = Fixed costs ÷ Gross margin %. A business with £120,000 of fixed costs and a 40% gross margin breaks even at £300,000 annual revenue. Reduce fixed costs by £20,000 and the break-even drops to £250,000 — a 17% reduction in required revenue. That is a significant buffer.
Step 1: Build a complete fixed cost audit
Most SME owners have a rough idea of their fixed costs but rarely have a complete, verified list. Start with your bank statements and accounting software. Identify every recurring payment that occurs regardless of sales volume. Group them into categories:
| Category | Typical items | Typical % of fixed cost base |
|---|---|---|
| People | Salaries, employer NI, pension, training | 50–70% |
| Premises | Rent, rates, utilities, service charge, insurance | 10–25% |
| Finance | Loan repayments, HP, leases, bank charges | 5–15% |
| Technology | Software subscriptions, IT support, hosting | 3–10% |
| Professional | Accountancy, legal, HR advisory | 2–8% |
| Other | Marketing retainers, vehicles, miscellaneous | 3–10% |
For each line, note: the annual cost, when the contract or commitment expires, and whether it is genuinely fixed or could be converted to variable.
The seven highest-impact areas for fixed cost reduction
1. Premises and rent
Commercial property is typically the second-largest fixed cost after people. Lease renewal is the optimal moment to renegotiate. UK commercial lease terms have shifted significantly since 2020 — shorter leases, break clauses, and rent-free periods are more negotiable than they were before hybrid working normalised. If you are within 24 months of lease renewal, begin the conversation now. Landlords prefer an existing tenant at reduced terms to a void period followed by new tenant fit-out costs.
Benchmark your cost per desk or per square metre against current market rates. If you are significantly above market, you have a negotiating case. If you are at or below market, use the renewal conversation to negotiate a break clause for flexibility.
2. Payroll efficiency
People are your largest fixed cost and the most sensitive to manage. The goal is not headcount reduction per se, but revenue per employee optimisation. An employee generating £200,000 of revenue is not a cost; an employee generating £50,000 of revenue in a business where the sector median is £120,000 is a fixed cost problem.
Review: utilisation rates (professional services), revenue attribution by team member (sales), and overhead ratio (support functions). Consider whether any fixed-salary roles could be partially converted to performance-related pay, effectively converting a fixed cost to a variable one.
3. Software and subscriptions
Software subscription creep is one of the most common and easily resolved fixed cost problems. The average UK SME has 4–6 software subscriptions that are unused or underused. A 30-minute audit of your bank statement, compared against a list of subscriptions actively used by your team this month, typically identifies £1,000–5,000 per year in redundant spend.
Annual contract reviews: any subscription on annual auto-renewal should be reviewed 90 days before renewal. Negotiate or cancel at this point — cancelling 30 days after auto-renewal means paying for another year.
4. Professional services retainers
Accountancy, legal, HR advisory, and marketing retainers are significant fixed costs that are often under-scrutinised. Review each retainer against actual utilisation in the past 12 months. If you have used 40% of your accountancy retainer’s capacity, you have two options: reduce the retainer scope or increase your utilisation of services you are already paying for. Do not automatically renew without a conversation about scope and value.
5. Insurance portfolio
Insurance is a fixed cost that SME owners rarely review. Run a competitive tender every two years minimum. Use a broker rather than going direct — brokers have access to markets and negotiation leverage that direct applicants do not. Combined business insurance policies are often cheaper than individual policies for each risk. If your business risk profile has changed (new premises, different headcount, changed product mix), re-declare accurately — over-insurance is as common as under-insurance.
6. Vehicle and asset financing
Lease and hire purchase agreements are fixed-cost commitments that persist regardless of revenue. Review each vehicle lease against actual business use. Vehicles used primarily for commuting rather than commercial purposes are a fixed cost with limited revenue linkage. At lease renewal, consider whether the same vehicles are needed, whether fewer vehicles at higher utilisation is more efficient, and whether the lease terms reflect current market rates.
7. Finance costs
Review all loan and overdraft arrangements. With the Bank of England base rate still elevated relative to the 2010s, refinancing may or may not be advantageous — model each specific arrangement. Look particularly at revolving credit facilities with commitment fees on the unused portion: if you are paying a fee for the right to draw an overdraft you do not actually use, either draw on it productively or reduce the commitment.
The fixed-to-variable conversion: Where possible, convert fixed costs to variable. A freelance specialist hired per project costs more per hour than a salaried employee but less in weeks when there is no work. A variable-rate delivery partner replaces a fixed-cost fleet. The trade-off is control and availability; the benefit is resilience when revenue is variable.
How fixed costs affect your break-even
Every £10,000 of annual fixed cost reduction at a 40% gross margin lowers your break-even by £25,000 of required revenue. Across a three-year period, £10,000 of annual savings compounded with a 4–5× EBITDA multiple adds £50,000–60,000 to your enterprise value at exit. Fixed cost management is not just an operational exercise; it is a valuation strategy.
Classify and model your cost structure
The 3DMAI Fixed vs Variable Cost Tool classifies your costs, calculates contribution margin, and shows your break-even point at different revenue levels.