Outsourced Bookkeeping vs In-House: A Cost Comparison for UK Businesses
Most business owners weigh up outsourced bookkeeping vs in-house by comparing a monthly fee against a salary. That comparison is wrong, because a salary is only part of what an employee costs. Employer National Insurance, pension contributions, software licences and recruitment all sit on top. This article sets out the full annual cost of both options for the 2026/27 tax year and identifies the point at which hiring in-house starts to make financial sense.
Quick Overview
- An in-house bookkeeper on a £30,000 salary costs roughly £34,000–£35,000 a year once employer National Insurance, pension and software are included.
- Employer NICs are charged at 15% on earnings above £5,000 a year in 2026/27, and the Secondary Threshold is frozen until 2031.
- The Employment Allowance of up to £10,500 can wipe out that NI cost entirely for eligible employers, which narrows the gap considerably.
- Outsourced bookkeeping typically costs £150–£600 a month for small UK businesses, rising to £600–£950+ for higher transaction volumes.
- Outsourcing is usually cheaper below roughly 20–25 hours of bookkeeping work a month, because you pay only for work performed.
- Hiring in-house becomes competitive once the workload reliably fills a full working week, or when daily cash, stock or credit control demands on-site presence.
Table of Contents
How much does an in-house bookkeeper cost in the UK?
Budget for 20–30% above the advertised salary. Indeed reports an average bookkeeper salary of around £28,894 in England, while Morgan McKinley’s 2026 guide puts the London range at £28,000–£38,000. The employment cost is what matters, not the headline figure.
The full cost stack for 2026/27
Cost component | Annual figure (£30,000 salary) |
Base salary | £30,000 |
Employer National Insurance (15% above £5,000) | £3,750 |
Workplace pension (3% of qualifying earnings) | £713 |
Bookkeeping software licence | £400–£600 |
Recruitment and onboarding | Variable |
Total (before recruitment) | £34,863–£35,063 |
Two figures drive that total. Employer National Insurance is charged at 15% on earnings above the Secondary Threshold of £5,000 a year, unchanged from 2025/26, and the threshold remains frozen until 2030–31. On the pension side, the minimum total contribution is 8% of qualifying earnings, of which the employer must fund at least 3%, calculated on the band between £6,240 and £50,270 for 2026/27.
The Employment Allowance changes the maths. Eligible employers can reduce their employer NI bill by up to £10,500 in 2026/27, and the previous £100,000 eligibility cap was removed from 6 April 2025. For a company that has not already used the allowance elsewhere, the £3,750 NI cost drops to nil, bringing total employment cost closer to £31,100. A single-director company with no other employees cannot claim it, but hiring a bookkeeper often creates eligibility.
One further point for 2026/27: the Employment Rights Act 2025 makes Statutory Sick Pay payable from day one and removes the earnings floor for eligibility. Absence now carries cost from the first day.
How much does outsourced bookkeeping cost?
Expect £150 to £600 a month for a typical UK small business. Fixed retainers generally run from £150 to £950 a month in 2026/27, with hourly rates between £20 and £50. Pricing follows transaction volume, the number of bank accounts, VAT status and whether payroll is included.
A rough guide to where businesses land:
- Sole traders and micro businesses: £150–£300 a month for light transaction volume
- Small VAT-registered companies: £300–£600 a month at around 100+ transactions
- Higher-volume businesses: £600–£950+ a month with 300 or more transactions, multiple bank accounts and payroll to reconcile
At £400 a month, the annual cost is £4,800. That figure carries no employer NI, no pension liability, no holiday or sick pay, and no recruitment cost. Software is frequently bundled, though this varies by provider, so confirm it before comparing quotes. Fees also step up for multi-currency accounts, stock, CIS and Making Tax Digital quarterly submissions.
Outsourced bookkeeping vs in-house: side-by-side comparison
Factor | In-house bookkeeper | Outsourced bookkeeping |
Typical annual cost | £31,000–£35,000+ | £1,800–£11,400 |
Employer NI and pension | Yes | No |
Holiday and sick cover | Your responsibility | Built into the service |
Software licence | Separate cost | Often included |
Scales with growth | Slowly, via hiring | Immediately, via service level |
Professional oversight | Depends on the hire | Regulated firm |
Availability | Fixed hours, on site | Agreed response times |
The cost gap only closes when the workload is large enough to occupy someone full time. Below that, an employee is paid for hours the business does not need.
When does hiring an in-house bookkeeper make sense?
Hiring is the better option when the work genuinely fills the week. Clear signals include:
- Daily cash handling, stock movements or trade counter sales
- Credit control that needs same-day chasing to protect cash flow
- Several trading entities with constant intercompany activity
- A finance function where bookkeeping is one of a wider set of duties
- Transaction volumes above roughly 500 a month across multiple accounts
The honest counterpoint is that many businesses hire too early, then fill the spare capacity with general admin. That masks the real cost of the decision and leaves the bookkeeping under-supervised.
Hidden costs most businesses miss
Four costs rarely appear in the comparison:
- Absence cover. Holiday and sickness leave the books unattended, and catch-up work after a gap often costs more than routine processing.
- No second review. A sole in-house bookkeeper has nobody checking the work, so coding errors and VAT misclassifications can run for months before a year-end review finds them.
- Training and CPD. Keeping current with VAT rules and MTD requirements for VAT-registered businesses is an ongoing cost.
- Your own time. Supervising, reviewing and answering queries pulls directors away from fee-earning work.
Which option is right for your business?
Work through these six questions:
- Does the bookkeeping workload reliably exceed 25 hours a month?
- Are you VAT registered, and does someone need to prepare returns?
- Do you handle daily cash or stock movements?
- Can you claim the Employment Allowance, or is it already used?
- Do you need management accounts as well as record-keeping?
- Would a fixed monthly fee suit your cash flow better than a salary?
Three or more “yes” answers to questions 1–3 point towards hiring. Otherwise, outsourcing is normally the more efficient route.
Costs vary by sector, location and transaction volume. Check all rates and thresholds against current GOV.UK guidance before making a hiring decision, and take professional advice on your own circumstances.
FAQ
Is outsourced bookkeeping cheaper than hiring in-house?
For most small businesses, yes. Outsourcing typically costs £1,800–£11,400 a year against £31,000+ for an employee, because you pay only for the work required rather than a full-time salary and its associated employment costs.
How much does a part-time bookkeeper cost in the UK?
A part-time bookkeeper working two days a week on a £30,000 full-time equivalent salary costs roughly £12,000–£13,500 a year, including employer NI and pension. Employer NI applies once earnings exceed £5,000 annually.
Can outsourced bookkeepers handle VAT returns and Making Tax Digital?
Yes. Most UK bookkeeping providers prepare and file VAT returns through MTD-compatible software such as Xero, QuickBooks or Sage, and maintain the digital records HMRC requires.
Is my financial data safe with an outsourced provider?
Providers regulated by a professional body must hold professional indemnity insurance and comply with UK GDPR. Ask about data storage location, access controls and their supervisory body before signing.
Conclusion
The outsourced bookkeeping vs in-house decision comes down to workload, not preference. Below a full week’s work, outsourcing costs a fraction of an employee once National Insurance, pension and software are counted. Above it, an in-house hire buys availability and control that a monthly service cannot match. Calculate the total employment cost, not the salary, and the answer usually becomes clear.
About The Author
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