VAT quarters and cash-flow gaps: how UK small businesses can plan for the VAT bill

Plenty of UK businesses are profitable on paper and still dread the VAT quarter. The money was never really theirs, but it sat in the bank account for weeks and quietly paid for stock, wages and rent.

This guide explains why the gap appears, how to see it coming, the HMRC options worth knowing about and how to decide whether short-term finance is the right tool or a warning sign.

Key takeaways: the VAT you charge customers belongs to HMRC, so treat it as a liability from the day you invoice; most VAT-registered businesses pay quarterly, about five weeks after each quarter ends, which creates a predictable lump; HMRC schemes such as cash accounting and annual accounting can change the timing, and Time to Pay can help in genuine difficulty; if you use finance for a VAT bill, arrange it early and make sure the underlying pattern is fixable.

Why does a VAT bill create a cash-flow gap?

Because VAT is collected continuously but paid in one go, the cash tends to be used for something else before the bill arrives.

Output VAT is the VAT you charge on your sales. Input VAT is the VAT you pay on your business purchases. Each quarter you pay HMRC the difference. If you charged more than you paid, you owe the balance; if you paid more, HMRC owes you a repayment.

The trouble is that output VAT lands in the same bank account as everything else. Over a quarter, it becomes indistinguishable from your own money. A strong sales quarter feels like a strong cash quarter, right up until the return is due and roughly a sixth of your VAT-inclusive takings (at the standard rate, before input VAT) needs to leave in one payment.

Three things make the gap worse:

• Late-paying customers. Under standard VAT accounting you owe the VAT once you've issued the invoice, even if the customer hasn't paid you yet.
• Growth. A rising quarter means a larger VAT bill, often at the same moment you're spending more on stock and staff to keep up.
• Coinciding deadlines. A VAT payment landing in the same month as Corporation Tax, a PAYE bill or quarterly rent can turn a manageable payment into a squeeze.

When is VAT due in the UK?

For most businesses on standard quarterly returns, the return and payment are due one calendar month and seven days after the end of the VAT quarter.

So a quarter ending 31 March is usually due by 7 May, and a quarter ending 30 June by 7 August. If you pay by Direct Debit, HMRC collects a few working days after the deadline. Your VAT quarters don't have to match calendar quarters: HMRC assigns stagger periods, and you can see yours in your VAT online account. Businesses on the Annual Accounting Scheme or making payments on account follow different timetables, so check your own dates on GOV.UK.

Returns must be filed using software compatible with Making Tax Digital, HMRC's system that requires VAT records to be kept digitally and submitted through approved software. That has a useful side effect: your software can usually show a running VAT liability at any point in the quarter, not just when the return is due.

How much should I set aside for VAT?

Set aside the VAT element of every sale as it comes in, less the VAT you've paid on purchases, and keep it in a separate account.

At the standard rate, the VAT inside a VAT-inclusive price is one sixth of that price. On a £1,200 sale including VAT, £200 is VAT. Rates and rules can change, so check the current figures on GOV.UK, particularly if you sell reduced-rate or zero-rated goods.

Many owners find it simpler to move a fixed percentage of takings each week into a dedicated VAT account, then true it up once a month against the figure in their accounting software. The point isn't precision. It's to stop VAT money being spent twice.

Here's an illustrative worked example for a business on standard VAT accounting:

In this illustrative case the business owes £18,000 about five weeks after the quarter ends. If it had set aside £5,000, £6,000 and £7,000 at the end of each month, the payment would be a non-event. If it hadn't, and some of month 3's customers were paying on 60-day terms, it could be looking for £18,000 at a point when a chunk of the related sales cash hasn't even arrived.

Which HMRC VAT schemes can help with cash flow?

The Cash Accounting Scheme, the Annual Accounting Scheme and the Flat Rate Scheme each change when or how you pay VAT, and one of them may suit your business better than standard accounting.

• Cash Accounting Scheme: you pay VAT on sales when your customer pays you, rather than when you invoice. That removes the problem of paying VAT on money you haven't received. The trade-off is that you reclaim input VAT only when you pay your suppliers. There's a turnover limit to join.
• Annual Accounting Scheme: you make advance payments towards your VAT bill through the year, based on your last return, then file one annual return and settle the balance. It smooths payments into smaller, predictable amounts. There's a turnover limit here too.
• Flat Rate Scheme: you pay a fixed percentage of VAT-inclusive turnover, set by business sector, and generally can't reclaim input VAT on most purchases. It simplifies the admin but doesn't suit every business, particularly those with heavy VAT-able costs.

Eligibility thresholds and flat-rate percentages are set by HMRC and change from time to time, so check the current figures on GOV.UK before assuming you qualify. It's worth a short conversation with your accountant: the right scheme depends on your margins, customer payment terms and how much VAT you pay on costs.

What happens if I can't pay my VAT bill on time?

Contact HMRC before the deadline, because late payment can lead to penalties and interest, and HMRC may agree a Time to Pay arrangement if you ask early.

Since 2023, HMRC has used a points-based system for late VAT returns and a separate regime of penalties and interest for late payment. The detail, including the rates and the timings at which penalties start, is set out on GOV.UK and can change, so check the current rules there rather than relying on a figure you remember.

A Time to Pay arrangement lets you spread a tax debt over instalments. HMRC will want to understand why you can't pay, what you can afford and how you'll stay current with future bills. It's designed for businesses that are viable but temporarily short, not as a routine way to fund the business.

Two points worth knowing. First, filing the return on time matters even if you can't pay in full, because late filing has its own consequences. Second, persistent VAT arrears can show up when you later apply for finance, because lenders often ask whether your tax affairs are up to date.

Should I use a business loan or credit to pay VAT?

It can be sensible for a one-off timing gap in a healthy business, but it shouldn't become the way every quarter gets paid.

Short-term finance for VAT makes most sense when the cause is clearly timing: a strong quarter where customers haven't yet paid, a large one-off order, or a coinciding bill that won't repeat. It makes less sense when the business is structurally short every quarter, because borrowing then just adds cost to a problem that needs fixing at source.

The main options UK SMEs use:

If the gap repeats every quarter, a revolving credit facility is often the neater fit, because you draw only for the weeks you need and repay as customer payments arrive. If late-paying customers are the root cause, invoice finance targets that directly. Our guide to revolving credit versus a business loan, in the Guides section, walks through the differences in more depth.

Whatever you choose, compare the total cost of borrowing against the cost of any HMRC penalties and interest, and read the offer carefully before you sign.

How do I build a VAT-aware cash-flow forecast?

Add each VAT payment to your forecast as a dated outflow, calculated from what you've actually invoiced and bought, not from last year's figure.

A 13-week rolling forecast, updated weekly, is enough for most small businesses. It covers a full VAT quarter plus a little more, so you always see the next payment coming.

1. Start with today's bank balance across all business accounts.
2. List expected customer receipts week by week, using realistic payment dates, not invoice due dates.
3. List fixed outgoings: rent, wages, loan repayments, subscriptions.
4. Add each tax payment on its due date: VAT, PAYE and National Insurance, Corporation Tax.
5. Pull the running VAT liability from your accounting software and check it matches your forecast figure.
6. Look for the lowest projected balance, and the week it occurs.
7. If that low point is uncomfortably close to zero, decide now what you'll do: move a payment, collect faster, adjust the VAT scheme or arrange a facility.

The seasonal version of this problem is covered in planning for the quiet months, and it's worth pairing with a year-end cash checklist so that VAT, Corporation Tax and year-end jobs are all on the same calendar.

How can I stop the VAT gap coming back each quarter?

Separate the money, shorten the time customers take to pay and match your VAT scheme to how your business actually trades.

• Open a dedicated VAT savings account and move money into it weekly or monthly.
• Tighten credit control: invoice promptly, state clear terms and follow up on the due date.
• Ask larger customers about faster payment options, and consider small early-settlement incentives where margins allow.
• Time big purchases with VAT reclaim in mind, so input VAT lands in the same quarter as the output VAT it offsets.
• Review your VAT scheme once a year with your accountant as turnover changes.
• Keep a small standby facility in place so a bad quarter doesn't force a rushed decision.

Lenders notice this discipline too. Regular VAT payments made on time, and a bank balance that doesn't hit zero every fifth week, are exactly the patterns described in what lenders see in your bank statements.

How Rook Bristol can help

Rook Bristol provides business loans, revolving credit, revenue-based finance, asset finance and invoice finance to UK-registered businesses, from £10,000 to £1 million over terms of up to 60 months. To apply, a business typically needs at least 6 months of trading and £10K or more in monthly turnover. We aim to make decisions quickly once we have your bank statements and company details.

If you can see a VAT gap coming, you can check your options or talk to our team before the deadline rather than after it. All finance is subject to status, and we can't give tax advice, so speak to your accountant or HMRC about your VAT position.