A cash flow forecast that only shows sales and supplier bills will look healthier than your bank. Tax is not optional timing. It lands on fixed dates whether customers pay early or late.
This guide is general information for UK small businesses. It is not a forecast of your firm, and it is not regulated tax advice. Confirm amounts and deadlines with your accountant and GOV.UK.
Cashwatch™ by Ask Alfred™ builds a 13-week view with tax timing in the same picture as debtors and outgoings. Alfred prepares the view. You decide what to do. Nothing regulated is submitted without a named professional.
Why tax-blind forecasts fail
Owners often build a grid of expected invoices and bills, then wonder why week seven still hurts. Common gaps:
- VAT: you may have collected output tax weeks ago, then pay HMRC in a later week.
- PAYE and NIC: wages leave the bank on payday; the tax and NIC usually follow on a later due date.
- Corporation tax: profit feels like cash until the company tax bill is due months after the year end.
If those lines are missing, the trough in your 13-week cash flow forecast is fiction.
What to put on the grid
Start with the blank in the cash flow forecast template UK guide, or the printable 13-week template. Then add tax as its own rows, not a vague "misc" line.
VAT
For most quarterly VAT returns, payment is due after the period ends (commonly one month and seven days for online submission). Put the expected payment in that week, not the week you raised the sales invoices. If you are on a different scheme (monthly, annual, cash accounting), use your actual due dates. See also the VAT return checklist and VAT return in the glossary.
PAYE and National Insurance
Payroll leaves the bank when you pay people. The PAYE and NIC you withhold usually leave later. Put both on the forecast: net wages on payday, and the HMRC payment on its due date. Confirm your scheme's exact dates with payroll or your accountant. See PAYE payment deadlines UK. Glossary: PAYE.
Corporation tax
For many companies, corporation tax is due nine months and one day after the end of the accounting period. That bill can sit outside a tidy monthly average and still smash a 13-week window if your year end is nearby. Estimate with your accountant; do not invent a number from last year's profit alone. See corporation tax payment deadline UK. Glossary: corporation tax and what is a CT600.
A calm weekly method
- List the next thirteen weeks of known tax dates (VAT, PAYE, corporation tax, and any other HMRC payment plans you are on).
- Add expected amounts from your last return, payroll run or accountant estimate. Mark anything that is still a guess.
- Place receipts and supplier payments as usual, with a cautious view of overdue invoices.
- Find the trough. Ask: is it a tax week, a payroll week, or a late-payer week?
- Act early: chase debtors, speak to your accountant about timing, or move non-critical spend. See when will my business run out of cash?
Tax in the forecast is not tax advice
Putting a payment on a grid does not decide how much you owe, which scheme you should use, or whether you can pay later. Alfred and this guide organise timing for planning. Regulated tax decisions stay with a qualified professional. For submission prep, see Tax prep.
What to read next
- 13-week cash flow forecasting explained
- Cash flow forecast template UK
- When will my business run out of cash?
- VAT return checklist
- What is a CT600
- Corporation tax payment deadline UK
- PAYE payment deadlines UK
- Cashwatch™
- Tax prep
- Glossary
This page is general information for UK small businesses. Deadlines and schemes can change. Check GOV.UK and your accountant for your situation. Nothing here is regulated advice, and nothing regulated should be submitted without human approval from a qualified professional.