Small business bookkeeping: the records the law expects and a system that keeps up

Small business bookkeeping tends to grow by accident. A spreadsheet became an accounting package, invoices sit partly in an inbox, and the accountant sorts it all out once a year. That holds until the tax authority asks for the invoice behind an old depreciation claim or a buyer asks for clean books.

The first-year basics are on tax and bookkeeping for new businesses. This page goes further for established businesses: records, retention, cash versus accrual, software, e-invoicing and outsourcing.

What must your business records contain?

Most tax systems do not prescribe a format. The US tax authority says that apart from a few cases no special kind of records is required, as long as your system clearly shows income and expenses (source: IRS, May 2026). Every system expects a trail from each figure in a return to a source document. Companies carry a broader duty: a UK company must record all money received and spent, its assets, its debts, its year-end stock and the goods it bought and sold, and directors who fail to keep records can be fined or disqualified (source: GOV.UK, January 2025).

How long do you have to keep business records?

The logic is similar almost everywhere: you keep records for as long as the tax authority can still check the return they support. The US ties retention directly to the period of limitations of each return (source: IRS, June 2026). Other countries set a fixed number of years. They differ most in when the clock starts and what extends it.

Checked October 2026. Company, employment and data protection law can set their own periods.

The start date matters for records that stay relevant for years. A machine depreciated over ten years supports a deduction each year, so keep its invoice until the retention period of the last such return has passed; UK guidance says the same for assets lasting more than six years (source: GOV.UK, January 2025). Treat leases and loans alike.

Keep digital records digital. In the Netherlands a printed copy of a digital file does not meet the retention requirement (source: business.gov.nl, October 2026), and Australia requires records that cannot be changed and data the tax office can extract in a standard format (source: ATO, June 2026). Keep e-invoices in their original format.

Check your country

• Period: how many years, from which date, and what extends it.
• Location: whether records may sit abroad or on foreign cloud servers.
• Language and format: national language, scanned paper, e-invoices, old software data.

Rules change; check the tax authority's page before destroying anything.

Cash or accrual accounting: which method fits your business?

The cash method records income when money comes in and expenses when you pay. The accrual method records income when earned and expenses when incurred, whenever payment happens (source: IRS, January 2022). In the UK the cash basis has been the default for the self-employed since the 2024 to 2025 tax year (source: GOV.UK, September 2026). In the US, corporations other than S corporations generally need accrual unless they pass a gross receipts test (source: IRS, January 2022). Company annual accounts are generally prepared on an accrual basis anyway.

Ingrid runs Brannock Tiles, a tile wholesaler with 14 staff that sells to builders on 30-day terms. Here is one year under both methods.

Fictitious Firmfocus example. Customers paid €2,870,000 of this year's invoices plus €240,000 from last year; Ingrid paid €1,960,000 of this year's purchase invoices plus €150,000 from last year. Tax is left out. The logic works in any currency.

The €250,000 gap is no error: customers owe €70,000 more than a year ago, suppliers were paid €60,000 faster and €120,000 more stock sits in the warehouse. Accrual shows what the business earned; cash explains why the bank balance barely moved. Accrual books plus a cash flow forecast give you both.

Choosing bookkeeping software for a growing business

• Tax returns: filing through the authority's digital channel. UK Making Tax Digital for Income Tax requires compatible software for sole traders and landlords above an income threshold from April 2026 (source: GOV.UK, August 2026).
• E-invoicing: sending and receiving invoices to the European standard EN 16931 (source: Your Europe, January 2026).
• Audit trail and roles: no deletions without a trace, separate rights for entering, approving and paying.
• Multi-currency: documented rates and automatic exchange differences; see exchange rates and currency risk.
• Links and exit: bank, payroll, stock and webshop feeds, plus a full export in a standard format.

E-invoicing: what is changing where

An e-invoice is issued, sent and received in a structured format (source: Your Europe, January 2026). A PDF by e-mail is readable for people, not for software, which is why Germany accepts it only during a transition (source: DIHK, October 2026).

Do your bookkeeping yourself or outsource it?

No business size makes outsourcing compulsory. The questions are whose time is cheapest for which task, and who checks whom.

Outsourcing the work does not outsource the responsibility: you stay liable for records and returns. Titles are protected differently per country, so ask about a firm's professional body and indemnity insurance.

How to set up bookkeeping that keeps up with the business

1. 01

   Separate the money flows

   Accounts for operations and tax reserves; no private payments.

2. 02

   Choose software against the checklist

   Migrate at a year end and keep the old data readable.

3. 03

   Book weekly, close monthly

   Reconcile bank, receivables, payables, stock and VAT on a fixed working day each month.

4. 04

   Put the figures to work

   Compare results with your budget in the Business Planner and your sector in the profit and cost benchmark; the finance function page turns this into a monthly review.

Small business or larger business

Pitfalls

• Counting retention from the invoice date: for assets, leases and loans the clock starts later.
• Printing digital invoices: the original file is the record.
• Losing data at a software switch: export before the old licence ends.
• Software without e-invoicing: it means a second migration soon.
• One person doing everything: whoever enters invoices should not approve and pay them.

Good records feed the rest of Finance, from the business taxes you file to the finance function that turns figures into decisions. Back to the knowledge base.