Bookkeeping is the process of recording every financial transaction a business makes. It is the foundation of all accounting – without accurate bookkeeping, financial statements, tax returns and management decisions are all built on unreliable data.
While accounting interprets and reports financial information, bookkeeping is the day-to-day work of capturing it. Every invoice sent, every payment received, every expense incurred needs to be recorded accurately and on time.
What bookkeeping covers
At its core, bookkeeping involves:
- Recording sales and income as they occur
- Recording purchases and expenses with supporting documentation
- Reconciling bank statements against recorded transactions
- Managing accounts receivable (money owed to you) and accounts payable (money you owe)
- Maintaining the general ledger – the master record of all financial transactions
These tasks feed into everything else your business does financially, from filing VAT returns to preparing year-end accounts.
Single-entry vs double-entry bookkeeping
There are two fundamental methods of bookkeeping.
Single-entry bookkeeping
Each transaction is recorded once, typically as a line in a cash book or spreadsheet. This works like a personal bank statement – you note what came in and what went out.
| Date | Description | Income | Expense | Balance |
|---|---|---|---|---|
| 1 Apr | Opening balance | £5,000 | ||
| 3 Apr | Client invoice paid | £2,400 | £7,400 | |
| 5 Apr | Office supplies | £180 | £7,220 | |
| 10 Apr | Software subscription | £49 | £7,171 |
Single-entry bookkeeping is only suitable for very small businesses with straightforward transactions. It does not track assets, liabilities or equity and makes it difficult to produce a proper balance sheet.
Double-entry bookkeeping
Every transaction is recorded in at least two accounts – a debit in one and a credit in another. This system ensures that the books always balance and provides a complete picture of the business’s financial position.
For example, when you receive £2,400 from a client:
| Account | Debit | Credit |
|---|---|---|
| Bank (asset) | £2,400 | |
| Sales revenue (income) | £2,400 |
Double-entry bookkeeping is required for any business that needs to produce proper financial statements and is the standard used by all modern accounting software.
UK legal requirements
Who must keep accounting records?
Every UK business must keep adequate accounting records, regardless of size. The specific requirements depend on your business structure:
| Structure | Key requirement | Governing legislation |
|---|---|---|
| Sole trader | Sufficient records to complete Self Assessment | Income Tax (Trading and Other Income) Act 2005 |
| Partnership | Records of income, expenses and partner shares | Partnership Act 1890, Income Tax Act |
| Limited company | Adequate accounting records showing financial position | Companies Act 2006, s386-389 |
| LLP | Same as limited company | Limited Liability Partnerships Act 2000 |
For limited companies, the Companies Act 2006 requires records that are sufficient to show and explain the company’s transactions, disclose the financial position of the company with reasonable accuracy at any time, and enable directors to ensure that any accounts prepared comply with the Act.
Record retention
HMRC requires you to keep records for specific periods depending on your situation:
- Self Assessment (sole traders) – 5 years after the 31 January deadline
- Limited companies – 6 years from the end of the accounting period
- VAT records – 6 years (or 10 years for the VAT Mini One Stop Shop)
For more detail on retention periods, see our guide on how long to keep accounting records.
The bookkeeping cycle
A typical monthly bookkeeping cycle follows a predictable pattern:
- Collect source documents – invoices, receipts, bank statements, contracts
- Record transactions – enter each transaction in the appropriate accounts
- Reconcile bank accounts – match recorded transactions against bank statements
- Review accounts receivable – follow up unpaid invoices
- Review accounts payable – ensure supplier payments are made on time
- Produce management reports – trial balance, profit and loss, aged debtors
Doing this consistently – weekly or at least monthly – prevents the backlog that causes errors and missed deadlines.
Cash basis vs accrual basis
UK sole traders and small businesses can choose between two bases of accounting:
Cash basis
You record income when you receive it and expenses when you pay them. This is simpler and aligns your records with your bank balance.
HMRC allows sole traders to use the cash basis if their turnover is below £150,000. You must switch to the accrual basis once your turnover exceeds this threshold.
Accrual basis
You record income when it is earned (when you invoice) and expenses when they are incurred (when you receive a bill), regardless of when money changes hands. This gives a more accurate picture of profitability but is more complex to manage.
| Factor | Cash basis | Accrual basis |
|---|---|---|
| When income is recorded | When received | When invoiced |
| When expenses are recorded | When paid | When incurred |
| Complexity | Lower | Higher |
| Accuracy of profit reporting | Can be misleading | More accurate |
| Turnover limit | £150,000 | No limit |
| Capital allowances | Limited (AIA only for cars) | Full capital allowances available |
All limited companies must use the accrual basis. The cash basis is only available to unincorporated businesses.
Digital bookkeeping
Paper-based bookkeeping is increasingly impractical. Making Tax Digital (MTD) already requires VAT-registered businesses to keep digital records and file VAT returns using MTD-compatible software. Since 6 April 2026, MTD for Income Tax has also applied to sole traders and landlords with qualifying income over £50,000, and the threshold falls to £30,000 from April 2027 and £20,000 from April 2028.
Digital bookkeeping tools offer significant advantages:
- Automated bank feeds import transactions directly from your bank account
- Receipt scanning captures expense data from photos of receipts
- Automated categorisation learns from your patterns to code transactions
- Real-time reporting gives you an up-to-date view of your financial position
- Error reduction through built-in validation and reconciliation tools
Common bookkeeping mistakes
- Falling behind – letting transactions pile up leads to errors and missed deductions
- Missing receipts – no receipt means no proof of the expense if HMRC enquires
- Mixing personal and business – complicates record-keeping and raises red flags
- Not reconciling regularly – bank reconciliation catches errors before they compound
- Incorrect VAT treatment – applying the wrong VAT rate or forgetting to claim input VAT
- Ignoring petty cash – small cash transactions still need recording
Bookkeeper vs accountant
These roles are related but distinct:
| Task | Bookkeeper | Accountant |
|---|---|---|
| Daily transaction recording | Yes | Sometimes |
| Bank reconciliation | Yes | Sometimes |
| VAT returns | Often | Yes |
| Year-end accounts | No | Yes |
| Tax planning | No | Yes |
| Financial analysis | No | Yes |
| Statutory audit | No | Yes (if qualified) |
Many small businesses handle their own bookkeeping using software and engage an accountant only for year-end accounts and tax returns. With the right accounting software, the bookkeeping workload is reduced significantly through automation, leaving less for either role to do manually.
Getting started
If you are setting up bookkeeping for the first time:
- Open a separate business bank account to keep transactions cleanly separated
- Choose your accounting method – cash basis or accrual basis
- Set up your chart of accounts to categorise transactions consistently
- Establish a routine – weekly is ideal, monthly at minimum
- Keep every receipt – digital copies are fine, see our receipt management guide
- Reconcile your bank account at least monthly
- Review your records before each VAT return or tax filing deadline