What is a Double Entry in Bookkeeping? A Complete Guide

A double entry is a record of one business transaction in two accounts: one showing where the money came from, and the other where it went. 

Double entries are the building blocks of double-entry bookkeeping, the system most businesses use to keep accurate financial records. Limited companies rely on it, and many sole traders adopt it too once their finances outgrow basic income and expenses. 

This guide explains exactly what double-entry bookkeeping is, how it compares with single-entry bookkeeping, and why it's the standard accounting method used by businesses of every size.

Key points

• Double-entry bookkeeping gives you more accurate financial reports 📊
  Because it tracks assets, liabilities, equity, income, and expenses, double-entry bookkeeping lets you produce reliable profit and loss accounts and balance sheets while making errors easier to spot.
• Most growing businesses benefit from this method 📈
  Limited companies are expected to use double-entry bookkeeping, while many sole traders and partnerships switch to it as their finances become more complex.
• Bookkeeping software does the hard work 💻
  You don't need to memorise debits and credits. Modern bookkeeping software records the correct entries automatically, reducing manual work and ensuring accurate records.
• ANNA keeps your bookkeeping organised 🚀
  ANNA categorises transactions, stores receipts, tracks invoices, estimates your taxes, and lets you file eligible tax returns, ensuring double-entry bookkeeping is easier to manage.

What is double-entry bookkeeping?

Double-entry bookkeeping is a method of recording each business transaction in two accounts. One entry shows where the money came from, and the other shows where it went.

This approach has been the foundation of accounting for more than 500 years, and it's still used by modern bookkeeping software. 

The accounting equation behind double-entry bookkeeping

This is the simple equation that keeps the balance in your accounts at all times:

Assets = Liabilities + Equity

Here's what each part means:

• Assets are resources your business owns, such as cash, equipment, stock, and unpaid customer invoices
• Liabilities are amounts your business owes, including loans, supplier invoices, and VAT owed to HMRC
• Equity represents the owner's interest in the business – this may include shareholders' funds for a limited company, or the capital they've put in as a sole trader

Every transaction changes at least two of these categories, but the equation always has to remain balanced.

For example, if your business takes out a £10,000 loan, this is what happens:

• Assets increase because your bank account receives £10,000
• Liabilities also increase because your business now owes £10,000 to the lender
• Equity doesn't change

The same idea applies to every transaction. If a customer pays an invoice, your bank balance increases while the amount they owe you decreases. If you pay for office supplies, your bank balance decreases while your office expenses increase. Both changes are recorded because they're part of the same transaction. 

Behind the scenes, these transactions are recorded using debits and credits. 

The chart of accounts, debits, and credits

Every business organises its transactions using a chart of accounts. It’s a list of the categories each transaction gets recorded against. 

Most charts fall into the same five groups: assets, liabilities, equity, income, and expenses. A sale gets recorded against an income account, an equipment purchase against an asset account, and so on. 

Every account has two sides: a debit side on the left and a credit side on the right. Debits and credits record which side a transaction goes on.

Here's how different account types behave:

For example, suppose a customer pays you £500.

Your business receives more cash, so your bank account increases with a debit. At the same time, you've earned £500 of income, so your sales account increases with a credit.

You don't need to memorise every rule. Most bookkeeping software creates the correct entries automatically when you record an invoice, payment, or expense.

What is a trial balance?

A trial balance is a report that checks whether your total debits equal your total credits.

Bookkeepers usually run a trial balance before preparing financial statements. If the totals don't match, there's likely an error somewhere in the records, such as a missing entry or a transaction posted to the wrong account.

A balanced trial balance doesn't guarantee that every transaction has been categorised correctly, but it does confirm that the bookkeeping follows the basic rules of double-entry accounting. 

Why is double-entry bookkeeping important?

Double-entry bookkeeping creates a complete record of your business finances, helping you understand not only how much cash you have, but also what your business owns, what it owes, and how profitable it is.

Using double-entry bookkeeping also helps you:

• Prepare accurate profit and loss accounts and balance sheets
• Spot errors before they become larger bookkeeping problems
• Keep reliable records for tax returns and statutory accounts
• Track assets, liabilities, and owner's equity alongside income and expenses
• Make better business decisions using accurate financial information

Double-entry vs single-entry bookkeeping

Single-entry bookkeeping records money coming in and going out, much like a personal bank statement. Many small businesses start this way because it's quick and easy to understand.

The downside is that it only tells part of the story. It doesn't properly track assets, liabilities, or unpaid invoices, and it doesn't provide the information needed to produce a balance sheet. It also makes bookkeeping mistakes harder to identify because there isn't a second entry to check against.

Double-entry solves all three of these issues at the cost of a bit more admin per transaction. 

Who needs to use double-entry bookkeeping?

Not every business is legally required to use double-entry bookkeeping, but it's the standard method for most businesses. Whether you need to use it depends on your business structure and the type of accounts you need to prepare. 

Limited companies

Limited companies are expected to keep accounting records that support their statutory accounts and Corporation Tax return. In practice, this means using double-entry bookkeeping because it produces a balance sheet as well as a profit and loss account.

Even if you have an accountant, they'll usually expect your records to follow double-entry principles.

Sole traders

Sole traders have more flexibility. If your business has straightforward income and expenses, you may be able to manage with simple cash records, especially if you use the cash basis for Self Assessment.

As your business grows, though, double-entry bookkeeping becomes much more useful, especially if you:

• Send invoices before customers pay you
• Buy stock to sell later
• Have business loans or other liabilities
• Want a clearer picture of your profits rather than just your cash balance

Partnerships

Partnerships have more than one owner, so the books need to track each partner's capital and share of the profits separately. 

Double-entry bookkeeping maintains capital and current accounts for each partner, making it far more straightforward to split profits and prepare the partnership accounts.

Common mistakes to avoid

Double-entry bookkeeping helps reduce errors, but mistakes can still happen, especially when entering transactions manually. Here’s what to be on the lookout for:

• Only recording one side of a transaction: Every entry needs a matching debit and credit. Miss one and your accounts won't balance.
• Using the wrong account: This won't affect the balance, but it will distort your reports. For example, coding equipment as an office expense rather than an asset can make your profit appear lower than it is.
• Mixing business and personal spending: This makes reconciling far harder and increases the chance of expenses being recorded incorrectly.
• Leaving bank reconciliation too late: Checking your books against your bank statements regularly catches missing or duplicate entries early. If you leave it until the last moment, the same job takes far longer and often clashes with a filing deadline.

🧠 Good to know:

Some transactions can be difficult to categorise correctly, especially if they involve assets, loans, or VAT. If you're unsure how something should be recorded, it's best to check with an accountant.

How ANNA makes double-entry bookkeeping easier

Whatever method your books use, keeping them accurate means categorising every transaction, attaching receipts, and staying on top of what you owe and what you're owed. 

ANNA does that legwork for you. 

With ANNA you can:

• Keep up-to-date books: Let Auto Accountant categorise your transactions automatically, and maintain accurate records with less manual work
• Manage your business finances in one place: Open a UK business account, send invoices, track payments, and record expenses from a single app
• Store your receipts digitally: Snap a photo of each receipt and attach it to the relevant transaction to keep your supporting records organised
• Stay on top of your taxes: Get real-time tax estimates and reminders about important filing deadlines, so you can avoid last-minute surprises
• File your tax returns with confidence: Prepare and submit VAT Returns, Self Assessment tax returns, and Company Tax Returns directly through ANNA, depending on your business
• Get help whenever you need it: Access 24/7, UK-based support for any questions about your account or bookkeeping.

Sign up for ANNA today to make bookkeeping, accounting, and tax admin much simpler.