- An opening balance is the amount in an account at the start of a new accounting period, carried over from the previous period’s closing balance.
- To calculate it, you take the prior period’s closing balance and apply any verified adjustments before the new period begins.
- Getting opening balances right matters more now that Making Tax Digital for Income Tax is in effect for sole traders and landlords earning over £50,000.
An opening balance is the amount of money in an account at the start of a new accounting period, carried straight over from the previous period’s closing balance. So if your bank account closed last year at £4,200, that same £4,200 becomes your opening balance on day one of the new year.
It’s the figure that keeps your books continuous, so every pound can be traced from one period to the next.
For a non-accountant founder, getting this one number right is what stops your accounts drifting out of line later, which is exactly where Sleek’s bookkeeping service helps. It also matters more than ever now that digital record-keeping rules are tightening.
What is an opening balance?
An opening balance is the value sitting in any account, such as your bank, cash, or a loan, at the very start of an accounting period. It carries directly over from the closing balance of the period before.
Think of it as the financial starting line for the year. Whatever you ended on last time is exactly where you begin this time.
For an existing business, the opening balance is never a fresh number you invent. It’s the previous year’s closing balance, brought forward so your records stay joined up. That continuity is what HMRC expects to see when it looks at your accounts, and it’s a core part of solid bookkeeping basics.
Opening balance vs closing balance
The opening balance shows where a period begins, while the closing balance shows where it ends. They are two ends of the same thread, and the closing figure of one period always becomes the opening figure of the next.
Feature | Opening balance | Closing balance |
When it applies | Start of the accounting period | End of the accounting period |
Where it comes from | Previous period’s closing balance | This period’s transactions and adjustments |
What it tells you | Your financial starting point | Your financial finishing point |
If your opening balance doesn’t match the prior closing balance, something has gone wrong, and that gap is the first thing to investigate.
How to calculate an opening balance, with a worked example
To calculate an opening balance, you take the closing balance from the previous accounting period and bring it forward, then apply any verified adjustments. In its simplest form the formula is:
Opening balance = previous period’s closing balance + or – any adjustments
Here’s a worked example carried through.
Imagine your business bank account closed the 2024/25 year with a balance of £4,200. That £4,200 becomes your opening balance for 2025/26.
Now suppose you later find a £150 supplier payment that cleared after year-end but belonged to the old period. You post that adjustment, and your corrected opening balance becomes £4,050.
The steps look like this:
- Find the closing balance for each account at the end of the last period.
- Carry that figure forward as the opening balance for the new period.
- Check it against your bank statements and records.
- Post any verified adjustments for transactions that belong to the prior period.
- Confirm the adjusted total reconciles before you start recording new activity.
Only adjust an opening balance when you can evidence the change with a statement or document. Adjusting on a hunch is how small errors snowball into a year of unreconciled accounts.
Opening balances when you start up or switch software
When you start a new business, your opening balance is simply whatever you put in to get going, such as money introduced by the owner, a business loan, or assets brought into the company. New businesses often forget to include setup costs like registration fees or equipment, so build those in from the start.
If you’ve just incorporated, it’s worth getting an accountant for your startup to set the first balances correctly, because errors here follow you for years.
Switching accounting software is the other common trigger. Most platforms such as Xero or QuickBooks let you import your closing balances directly as opening balances, but the import is only as accurate as the figures you feed it.
Before you migrate, reconcile your old closing balances against your bank statements. A clean migration depends on a clean starting point, which is also the foundation for staying compliant with Making Tax Digital for small business reporting.
Common opening balance mistakes and adjustments
The most common opening balance mistake is a figure that doesn’t match the previous period’s closing balance, usually caused by unposted transactions or missed adjustments. Catching these early keeps your whole year on track.
Watch for these recurring issues:
- Missing an account entirely, such as a loan, petty cash, or a second bank account, so the books never reconcile.
- Opening figures that don’t match last period’s closing figures, pointing to unposted entries.
- New businesses leaving out setup costs like equipment or registration fees.
- Timing differences where a payment clears in one period but belongs to another.
- Importing balances into new software without checking them against bank statements first.
Accurate opening balances also keep your downstream filings clean. A wrong starting figure can ripple through your profit, your VAT, and your year-end accounts and corporation tax, so it pays to fix it at source.
This matters more in 2026. Making Tax Digital for Income Tax is now in effect for sole traders and landlords with qualifying income over £50,000, which means accurate digital records, starting with correct opening balances, are a legal requirement rather than good practice.
How Sleek helps with opening balances
Opening balances are simple in theory but easy to get wrong in practice, especially when you’re starting up or migrating software. One wrong figure at the start can quietly distort every report that follows.
Sleek’s bookkeeping service sets your opening balances correctly from day one, so your books reconcile and your filings stay clean. If you’d rather hand the whole thing over, our accounting service keeps your records accurate and HMRC-ready all year round.
Disclaimer: The preceding information is not legal advice. This content is aimed to provide general guidance. For more formal or legal advice, contact Sleek directly.
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FAQs on opening balances
What is the opening balance for a new business?
For a brand new business, the opening balance is whatever you start with on day one. This is usually money introduced by the owner, a business loan, or assets brought into the company. Unlike an existing business, there’s no prior closing balance to carry forward, so your opening balance reflects your initial funding and any setup costs incurred.
Is the opening balance the same as the closing balance?
Yes, in timing terms. The closing balance at the end of one accounting period becomes the opening balance at the start of the next. They are the same figure viewed at two different moments. If your new opening balance doesn’t match the previous closing balance, it signals an error such as an unposted transaction that needs investigating.
How do I find my opening balance in Xero?
In Xero, opening balances are entered or imported when you first set up your accounts, usually drawn from your previous system’s closing balances. You’ll find them under your conversion balances settings. Always reconcile these against your bank statements before relying on them, because an inaccurate import will distort every report that follows during the year.
Why is my opening balance wrong after switching software?
This usually happens because closing balances were imported without being reconciled first. Missing accounts, duplicated entries, or transactions posted to the wrong period are the common culprits. Check that every account from your old system carried over, then match each opening figure against your final bank statements before recording any new transactions.
Does the opening balance include cash and bank?
Yes. An opening balance applies to every account you hold, including cash, bank, loans, and assets. Each account carries its own opening balance forward from the prior period. A complete set of opening balances across your whole chart of accounts is what allows your books to reconcile properly from the first day of the period.
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How often should I check my opening balances?
Check your opening balances whenever you close accounts, switch accounting systems, or at least once a year at the start of a new period. If your business is new, review them after your first period of trading. Regular checks catch small discrepancies before they compound into larger reconciliation problems across the year.
Can I correct an opening balance myself?
Yes, but only when you can evidence the change. A genuine adjustment should be backed by a bank statement, invoice, or other document showing a transaction belongs to the prior period. Correcting figures without supporting evidence risks introducing fresh errors, so many founders prefer an accountant to review opening balance adjustments before they’re posted.
