UK Startup

Templates · Finance

12-month cashflow forecast

Profit is opinion, cash is fact. A simple monthly forecast — what's coming in, what's going out, and what's left — is the single most useful spreadsheet a UK business owner can keep.

Last updated May 2026Reviewed against UK gov.uk sources

Most businesses don't fail because they're unprofitable. They fail because they run out of cash in a month their accountant told them was 'good'. A cashflow forecast is the antidote — and it doesn't need to be sophisticated. The template below is the model we use with founders, broken down into the inflows and outflows that catch people out.

Direct answer

Profit is opinion, cash is fact. A simple monthly forecast — what's coming in, what's going out, and what's left — is the single most useful spreadsheet a UK business owner can keep. Use the key facts, step list and official source links on this page to confirm the decision before you spend money or register anything.

12-month cashflow model (paste into a spreadsheet)

12-MONTH CASHFLOW FORECAST (£) M1 M2 M3 M4 M5 M6 M7 M8 M9 M10 M11 M12 OPENING BALANCE 5000 4150 4400 5450 6300 7350 8000 9050 10100 11550 12600 13950 INFLOWS Sales — recurring 3000 3300 3600 3900 4200 4500 4800 5100 5400 5700 6000 6300 Sales — one-off 500 800 600 900 700 500 800 700 900 600 700 900 Other (grants/loan) 0 0 0 0 0 0 0 0 0 0 0 0 TOTAL INFLOWS 3500 4100 4200 4800 4900 5000 5600 5800 6300 6300 6700 7200 OUTFLOWS Salaries (net) 1500 1500 1500 1500 1500 1800 1800 1800 1800 1800 1800 1800 PAYE & NI (to HMRC) 600 600 600 600 600 720 720 720 720 720 720 720 Rent 800 800 800 800 800 800 800 800 800 800 800 800 Software & SaaS 150 150 150 150 150 150 150 150 150 150 150 150 Marketing 300 400 300 400 300 300 400 300 400 300 400 300 Travel & expenses 100 150 100 150 150 100 150 150 100 150 100 150 Accountant 80 80 80 80 80 80 80 80 80 80 80 80 Insurance 50 50 50 50 50 50 50 50 50 50 50 50 Bank charges 15 15 15 15 15 15 15 15 15 15 15 15 Drawings/dividends 500 500 500 500 500 500 500 500 500 500 500 500 VAT to HMRC (qtrly) 0 0 250 0 0 400 0 0 500 0 0 600 Corporation Tax 0 0 0 0 0 0 0 0 0 0 0 1500 TOTAL OUTFLOWS 4095 4245 4345 4245 4145 4915 4665 4565 4615 4565 4615 6665 NET CASHFLOW -595 -145 -145 555 755 85 935 1235 1685 1735 2085 535 CLOSING BALANCE 4405 4005 3860 4415 5170 5255 6190 7425 9110 10845 12930 13465

Section 01

How to use this template

  • Copy into a spreadsheet (Numbers, Excel or Google Sheets).
  • Replace the example figures with your own monthly forecast.
  • Update actuals at month-end and roll the forecast forward.
  • Track variance — anything more than 15% off forecast is worth understanding.

Section 02

The line items most people forget

  • VAT — quarterly lump sums that can be 20% of inflows. Easiest cashflow killer.
  • Corporation Tax — annual, due 9 months after year-end.
  • Self Assessment payments on account — 50% of last year's bill in January and July.
  • Employer NI on salaries — 15% on top of gross pay (2025/26 rate).
  • Pension auto-enrolment contributions.
  • Annual subscriptions billed once a year — domain renewals, accounting software upgrade.

Section 03

Three rules for a useful forecast

  • Be pessimistic on sales. Multiply your gut forecast by 0.7 for the first six months of any new business.
  • Be generous on costs. Round every line up, and add a 10% contingency line.
  • Forecast cash, not invoices. The day money lands matters more than the day you billed.

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