The chart of accounts is the list of categories every transaction in your business gets dropped into. A well-designed one tells you exactly which products are profitable, which costs are creeping, and which areas need attention. A badly designed one hides all of that under generic buckets. This guide walks through how to design a chart of accounts that pays for itself.
What a chart of accounts actually is
It's a structured list, organised by the five account types (assets, liabilities, equity, income, expenses), with each line representing a category of transactions. Most UK SMEs have between 60 and 150 active accounts. Xero, QuickBooks, and FreeAgent all ship with a default chart that's a fine starting point but rarely the right end point.
The four design principles
1. Group by decision, not by transaction
The purpose of an account is to answer a question. "How much do I spend on marketing?" should be answerable in one line. If your chart has "Google Ads," "Facebook Ads," "LinkedIn Ads," "SEO," "Content," and "Events" as separate lines, you can see channel-level performance. If it has just "Advertising," you can't. Design accounts to match the decisions you make.
2. Don't over-engineer
The opposite mistake is just as bad. We've seen charts with 400 accounts where every supplier has its own line. That's not a chart of accounts, it's a supplier list. Suppliers go in your contacts, not your chart. A good rule: if you wouldn't make a different business decision based on splitting an account in two, don't split it.
3. Match the tax return
Corporation tax computations and self-assessment returns ask for specific cost categories: cost of sales, staff costs, premises, repairs, motor, travel, etc. Mirroring those categories in your chart makes year-end painless. Our accounts preparation team spends less time (and bills less) on clients whose charts map cleanly to the tax return.
4. Reserve room for growth
Number your accounts with gaps — 4000, 4010, 4020 instead of 4000, 4001, 4002 — so you can insert new categories later without renumbering. Most cloud platforms let you use any numbering, but a sensible scheme makes report ordering predictable.
A model UK SME chart structure
Income (4000–4999)
- 4000 Services revenue
- 4010 Product revenue
- 4020 Subscription revenue
- 4100 Other income
- 4200 Foreign exchange gains
Split revenue by what you sell, not by who you sell to. Customer-level detail belongs in reports, not the chart.
Cost of sales (5000–5999)
- 5000 Direct labour
- 5100 Materials
- 5200 Subcontractors
- 5300 Carriage and freight
Only costs that scale with revenue go here. Fixed overheads stay below.
Overheads (6000–7999)
- 6000 Premises (rent, rates, utilities)
- 6100 Staff (salaries, NIC, pension, training)
- 6200 Marketing (by channel)
- 6300 Software and IT
- 6400 Professional fees (legal, accounting, consulting)
- 6500 Travel and subsistence
- 6600 Motor
- 6700 Insurance
- 6800 Depreciation
- 6900 Bank charges and interest
Balance sheet (1000–3999)
Standard groupings: fixed assets, current assets, current liabilities, long-term liabilities, equity. Most defaults are fine here; just make sure director's loan and dividend accounts are clearly separated.
The tax-efficiency angle
A clean chart makes it obvious where tax planning opportunities live:
- R&D tax credit eligible costs get their own sub-accounts under cost of sales — easier to identify at claim time.
- Capital allowance items sit clearly in fixed assets with sub-accounts for AIA, special rate, and main pool.
- Entertaining is split between staff (tax-deductible up to £150 per head) and client (not deductible).
- Director benefits (medical insurance, gym, mobile) sit in dedicated accounts so P11D prep is fast.
Our tax planning team always reviews the chart of accounts as part of any planning engagement. It's that fundamental.
VAT categories within the chart
Each account should have a default VAT code (20% standard, 5% reduced, 0% zero-rated, exempt, outside scope). Setting this once means every transaction posted to that account gets the right VAT treatment automatically. Reviewing the default codes annually catches drift — VAT rules change and so do the products you sell.
What not to do
- Don't create a "Miscellaneous" or "Sundries" account. It becomes a graveyard.
- Don't lump all software into one line. Split critical-business software (accounting, CRM) from general (Microsoft 365).
- Don't separate every supplier. That's what supplier ledgers are for.
- Don't leave the default UK chart unchanged. Every business is different; the defaults are generic.
When to redesign
The right time to review your chart is now if you've never done it, or annually if you have. Triggers for a redesign: a new product line, a new tax regime (VAT registration, MTD ITSA), a funding round, or an upcoming sale of the business. We rebuild charts on every onboarding as part of our cloud bookkeeping service.
How the chart links to KPIs
Every KPI you might want — gross margin by product, customer acquisition cost, contribution margin, software spend per head — depends on the chart letting you isolate the right numbers. If you can't pull a KPI in two clicks from your chart, the chart needs work. We cover KPI design in another post in this series.
Spend a focused hour on your chart of accounts and it will repay you for years. It's the cheapest, highest-leverage piece of bookkeeping infrastructure you'll ever build.