How much VAT cash should you set aside?

Start with the payment date

A VAT total on an invoice is not the same thing as spare cash. Part of a customer receipt may ultimately be due to HMRC after eligible input VAT and return adjustments are considered. The useful planning question is how much cash should remain available until the return has been completed and the actual payment is known.

HMRC says VAT-registered businesses usually submit a return every three months. The usual online filing and payment deadline is one calendar month and seven days after the end of the accounting period. Put the actual deadline from the VAT online account into the cash-flow forecast first and allow enough time for the payment to reach HMRC.

Estimate output VAT cautiously

List the sales expected to fall into the VAT period and separate them by VAT treatment. The UK standard rate is currently 20%, while reduced-rated, zero-rated and exempt supplies need different handling.

For a simple standard-rated example, £72,000 of forecast sales excluding VAT produces estimated output VAT of £14,400. If the customer price already includes 20% VAT, the VAT within that price is one-sixth of the inclusive amount.

Do not apply 20% blindly to total bank receipts. Deposits, mixed rates, credit notes, overseas transactions and special schemes may change the return.

Estimate recoverable input VAT separately

Next, list expected business purchases and the VAT that may be reclaimable. Support the estimate with valid invoices and distinguish business use from private use.

If the illustrative business expects £4,800 of recoverable input VAT, estimated net VAT before other adjustments is £14,400 minus £4,800, or £9,600. That is a working forecast, not the finished return. Missing invoices, partial business use and adjustments can all change it.

Set the reserve from evidence

Build the reserve from known VAT already collected, expected VAT from invoices likely to be paid before the period closes and a cautious allowance for unresolved evidence or timing differences. Reconcile it to the VAT account and accounting records regularly.

Use the VAT Reserve Planner to compare estimated output VAT, recoverable input VAT, adjustments and cash already reserved. Use the VAT Calculator to separate VAT-inclusive and VAT-exclusive amounts. Neither replaces the records used for the actual return.

• Keep the reserve visible instead of treating it as normal operating cash.
• Refresh the estimate after material sales, purchases, credit notes or corrections.
• Do not reduce the reserve merely because the current bank balance looks comfortable.

Put the reserve into a downside forecast

Assume the illustrative £9,600 payment is expected in October. Show customer receipts in the month they are realistically expected to clear, supplier payments when they should leave the bank and the VAT forecast in October.

Then move one large customer receipt into the following month without moving payroll or supplier payments. If the downside forecast falls below zero, the VAT estimate may be reasonable while the payment plan remains fragile. The next action is about collections, spending, funding or early professional advice—not changing the VAT estimate to make the cash forecast look better.

Account for the VAT scheme you actually use

Under normal VAT accounting, VAT on sales may need to be reported before the customer pays the invoice. HMRC’s Cash Accounting Scheme generally links output VAT to customer payments and input VAT recovery to supplier payments.

Use a short monthly routine even when returns are quarterly: reconcile VAT records, refresh output and input VAT estimates, compare the estimate with cash reserved, update the payment date and test delayed receipts. This is a planning reserve rather than a VAT Return or personalised tax recommendation.

Official sources

• GOV.UK: VAT rates
• GOV.UK: When to do a VAT Return
• GOV.UK: VAT Cash Accounting Scheme
• GOV.UK: Keeping VAT records