If your business has quiet months followed by frantic ones, the way you pay for accounting matters more than you might think. A fixed fee accountant UK arrangement sounds simple. You pay one amount each month. Your books get done. Your tax returns get filed. No surprises.

Hourly billing sounds fair in principle. You only pay for the time used. But when your workload spikes, so does your bill. And when things are quiet, you might be paying for time that never gets used.

This article compares both models specifically for businesses with erratic workloads. Seasonal traders, project-based consultancies, contractors between contracts, and any business where activity levels vary month to month. We will use real numbers and real scenarios.

How Fixed Fee Accounting Works in Practice

A fixed fee arrangement means you pay a set monthly amount for a defined scope of work. That scope typically includes bookkeeping, VAT returns, payroll, management accounts, year-end accounts, corporation tax returns, and self assessment filings. Some firms include ad hoc advice within the fee. Others charge separately for anything outside the agreed scope.

For a limited company director in Manchester running a seasonal landscaping business, a fixed fee might be £200 per month in winter and £200 per month in summer. The work involved is very different. Summer means high turnover, more invoices, more VAT work, and more payroll hours. Winter means minimal activity. But the fee stays the same.

The fixed fee accountant UK model works because the accountancy firm averages out the workload across their client base. Your quiet months subsidise your busy months. The firm gets predictable revenue. You get predictable costs.

What Is Typically Included in a Fixed Fee

Most fixed fee packages for a limited company include:

  • Monthly or quarterly bookkeeping (bank reconciliation, invoice processing, expense coding)
  • Quarterly VAT returns (standard or flat rate)
  • Payroll processing (including RTI submissions, pension contributions, P32, P60, P45)
  • Year-end accounts preparation (balance sheet, profit and loss, directors' report)
  • Corporation tax return (CT600) and computation
  • Personal tax return (SA100) for the director
  • Confirmation statement filing
  • Ongoing tax planning advice (usually capped at a certain number of calls or emails)

Some firms also include Xero, FreeAgent, or QuickBooks subscription within the fee. Others charge it separately. Always check what software is included and what is not.

How Hourly Billing Works in Practice

Hourly billing means you pay for the actual time your accountant spends on your work. Rates vary widely. A junior bookkeeper might charge £40 to £60 per hour. A senior manager or director might charge £150 to £250 per hour. Specialist work like R&D tax credit claims or international tax can go higher.

For a business with erratic workload, hourly billing can feel fair during quiet months. You might only need 2 hours of bookkeeping at £50 per hour. That is £100 for the month. Compare that to a fixed fee of £200 per month, and you are ahead by £100.

But then comes the busy period. Year-end accounts, a complex VAT query, a HMRC compliance check, or a director's loan account that needs unwinding. Suddenly you are looking at 15 hours in a month at £150 per hour for the senior work. That is £2,250 in one month.

Over a full year, the total cost depends entirely on how many hours you actually use. And here is the problem. With hourly billing, you have no incentive to keep your accountant efficient. Every extra question costs you. Every call. Every email. Every bit of hand-holding.

Real Numbers: Fixed Fee vs Hourly for Three Business Types

Scenario 1: Seasonal Landscaping Business (Ltd Company)

A two-director landscaping company based in Bristol. Turnover of £180,000 per year. 80% of revenue comes between April and October. November to March is quiet, with minimal work and some retainer income.

Fixed fee option: £250 per month all year. Total annual cost: £3,000.

Hourly billing option: Quiet months (November to March) average 3 hours per month at £60 per hour. That is £180 per month for 5 months, totalling £900. Busy months (April to October) average 12 hours per month at £60 per hour for bookkeeping and £150 per hour for year-end work. That is £720 per month for 6 months, plus an extra 10 hours of senior time in September for year-end prep at £150 per hour (£1,500). Total busy period cost: £4,320 plus £1,500 equals £5,820. Annual total: £6,720.

In this scenario, the fixed fee saves £3,720 per year. The business avoids paying a premium for the seasonal spike.

Scenario 2: Freelance Consultant (Sole Trader)

A freelance marketing consultant in London. Turnover of £65,000 per year. Workload is erratic. Some months she earns £10,000. Others she earns nothing between projects. She does her own bookkeeping using FreeAgent and only needs year-end accounts and a self assessment return.

Fixed fee option: Most firms charge sole traders less than limited companies. A typical fixed fee for a sole trader with straightforward affairs is £80 to £120 per month. Let us use £100 per month. Annual cost: £1,200.

Hourly billing option: She only needs 6 hours of accountant time per year for the year-end and tax return. At £120 per hour, that is £720. She also has two ad hoc queries during the year, each taking 1 hour. Total: £960.

In this scenario, hourly billing saves £240 per year. But there is a catch. The fixed fee often includes ongoing advice throughout the year. If she needs to ask a question about IR35 for a new contract, or whether to register for VAT voluntarily, the fixed fee covers it. Hourly billing would add another £120 per call.

Scenario 3: IT Contractor Between Contracts (Ltd Company)

An IT contractor in Manchester. He works through his own limited company. He is on a 12-month contract earning £500 per day. Then he takes 3 months off between contracts. His accounting needs are steady during the contract (monthly bookkeeping, VAT returns, payroll). During the gap, he has no income and no activity beyond filing a nil VAT return.

Fixed fee option: £180 per month all year. Total annual cost: £2,160.

Hourly billing option: During the contract (9 months), he needs 4 hours per month at £60 per hour. That is £240 per month for 9 months, totalling £2,160. During the gap (3 months), he needs 1 hour per month at £60 per hour. That is £60 per month for 3 months, totalling £180. Annual total: £2,340.

In this scenario, the fixed fee saves £180 per year. Not a huge difference, but the fixed fee also covers any ad hoc queries about IR35 or dividend planning during the contract. Hourly billing would add more.

When Fixed Fee Accounting Costs You More

The fixed fee model is not always cheaper. It costs more when your accounting needs are genuinely low all year. A sole trader with simple affairs, no VAT, no payroll, and no ad hoc queries will almost certainly pay less on hourly billing.

It also costs more if your accountant's fixed fee includes services you do not need. Some firms bundle in management accounts, credit control, or CFO advisory services. If you do not use them, you are paying for something you do not value.

And some fixed fee agreements have hidden escalation clauses. The fee might be fixed for the first year, then increase by 10% or 20% annually regardless of workload. Read the small print.

When Hourly Billing Costs You More

Hourly billing costs more when your workload spikes, when you ask lots of questions, or when your accountant is inefficient. If your accountant takes 10 hours to do something another firm does in 5, you pay double for no extra value.

It also costs more when you are disorganised. If you send your accountant a shoebox of receipts and incomplete records in April, they will charge you for the time it takes to sort it out. A fixed fee accountant UK firm will absorb that inefficiency up to a point, then charge you extra above a threshold.

And hourly billing creates a perverse incentive. The more time your accountant spends on your work, the more they earn. That is not necessarily malicious. But it does mean you have to monitor the time yourself. Most business owners do not have the time or expertise to do that.

The Hidden Costs of Switching Between Models

If you switch from hourly to fixed fee mid-year, or vice versa, there are transition costs. Your new accountant needs to onboard your data. That takes time. If you are on a fixed fee, the onboarding is usually included. If you are on hourly billing, you pay for every minute of the handover.

There is also the cost of getting it wrong. If you choose hourly billing and your workload spikes unexpectedly, you might end up with a £5,000 bill in a single month. If you choose a fixed fee and your business closes down, you might be locked into a 12-month contract with no way out.

Most fixed fee agreements run for 12 months with a notice period of 30 to 90 days. Hourly billing is usually month to month. That flexibility has real value for businesses with uncertain futures.

What to Look for in a Fixed Fee Agreement

If you decide a fixed fee accountant UK model suits your business, check these details before signing:

  • Scope of work: Exactly what is included? Is it just compliance (accounts, tax returns) or does it include advisory work like tax planning, cash flow forecasting, and business structure reviews?
  • Volume caps: Is there a limit on the number of calls, emails, or hours per month? Some firms cap advice at 2 hours per month and charge extra above that.
  • Software costs: Is Xero, FreeAgent, or QuickBooks included in the fee or charged separately?
  • Annual increase: How much does the fee go up each year? Is it fixed for the first year only?
  • Exit terms: What is the notice period? Can you cancel if your business closes or you sell it?
  • Extra services: What happens if you need something outside the scope, like an R&D tax credit claim, a share scheme, or a CGT planning exercise? Is there a separate fee schedule?

As ICAEW qualified accountants, we see both models work well for different businesses. The key is matching the model to your workload pattern, not just picking the one that sounds cheapest.

How to Decide Which Model Fits Your Business

Start by mapping out your accounting workload across a typical year. List the months where you have high activity, low activity, and medium activity. Estimate the hours you think you need in each month. Then get quotes from at least three firms for both models.

For a seasonal or project-based business, the fixed fee model usually wins on total cost and predictability. You avoid the spike in busy months. You get unlimited (or capped) advice during quiet months. And you can budget accurately because the cost does not change.

For a very simple business with minimal transactions and no VAT or payroll, hourly billing is often cheaper. But be honest about how many ad hoc questions you ask. If you are the type of business owner who calls your accountant once a week, hourly billing will hurt.

For a contractor between contracts, the fixed fee model provides continuity. You keep the same accountant. You do not have to re-engage them every time you start a new contract. And the cost is the same whether you are earning or not.

The Bottom Line on Fixed Fee vs Hourly Billing

There is no universal right answer. The right model depends on your workload pattern, your need for advice, and your tolerance for variable costs.

If you have a seasonal or erratic business, the fixed fee accountant UK model typically saves you money over a full year. It also gives you peace of mind. You know what you are paying each month. You can focus on your business instead of watching the clock.

If your business is very simple and you rarely need advice, hourly billing will almost certainly be cheaper. Just be prepared for the occasional spike when something goes wrong or when year-end comes around.

Either way, get the agreement in writing. Understand what is included and what is not. And if your workload changes significantly, revisit the decision. What works for one year might not work for the next.

If you want to talk through the numbers for your specific business, get in touch with our team. We can run the comparison for you and recommend the model that fits your workload.