By Cody, Any Guru’s AI-assisted editorial author. Researched 27 October 2026.
A busy order book can sit beside an uncomfortable bank balance. You may need to pay people, buy materials or renew insurance before the money from completed work arrives. A monthly total can look reassuring while one particular Tuesday is difficult.
A 13-week cash flow forecast gives you a short, rolling view of those timing gaps. The useful output is a dated decision: which week needs attention, what assumption could change it, and who will act before then?
This guide is for UK founders and small-business owners building that practical view. It is general planning information, not personalised financial, tax, legal or insolvency advice. Ask your accountant to check the assumptions that matter to your business.
Choose the question before opening a spreadsheet
Start with something concrete: “Can we cover the next payroll if our biggest customer pays two weeks late?” or “What happens if we order materials before a new project starts?”
Thirteen weeks is a useful working window, not a legal requirement or a universally sufficient horizon. If your delivery and payment cycle is longer, extend the view. The British Business Bank’s forecasting guidance recommends covering at least your cash flow cycle.
Keep longer-term planning alongside this weekly view. Business.gov.uk’s funding guidance describes a 12-month forecast for funding preparation. A short-term working sheet does not replace a funder’s requirements.
Build the first version from evidence
Gather your current bank positions, unpaid customer invoices, supplier bills, payroll schedule, debt repayments and known renewals. Add tax payment amounts and dates confirmed through your records or adviser. Record when you last checked each input.
Use thirteen columns headed with actual week-starting dates. Give cash movements their own rows, then add opening balance, total receipts, total payments, net movement and closing balance.
Start with cleared bank balances. Show borrowing facilities separately so available credit is not mistaken for money already in the account. Make restrictions on money visible too: for example, a grant’s spending conditions need checking against its agreement rather than assuming the whole balance can fund any expense.
Keep transfers between your own business accounts out of the consolidated receipts and payments totals. Otherwise moving money between accounts can make activity look larger without creating extra cash.
Put money in the week it is likely to move
An invoice raised on Monday is not Monday’s cash receipt. For each substantial amount, record its expected payment date and the evidence: an agreed schedule, a customer’s confirmation or the customer’s actual payment history.
Keep a separate notes column for uncertain opportunities. A proposal awaiting approval should not quietly become a certain cash receipt. For a new business with little history, document the assumption and revisit it as evidence arrives.
Likewise, show card or marketplace receipts when they are expected to settle. Avoid counting the full sale and the later settlement as two separate inflows. Identify fees consistently, with your bookkeeper’s help where needed.
The Insolvency Service’s cashflow guidance for directors highlights that growth can create cash pressure and that payment delays need considering. More sales can mean more cash committed before collection.
Make payments visible before they become surprises
Separate recurring costs from less frequent commitments. A quiet-looking week can contain annual insurance, a supplier deposit or an equipment payment.
Include the cash that will actually leave the bank, not just costs recognised in your profit calculation. Use a consistent treatment of VAT and related payments, checked with your accountant; do not mix net and gross figures or count the same payment twice. Show business drawings or distributions where relevant without treating this sheet as permission to make them.
Use these two relationships for every week:
- Net movement = total receipts minus total payments.
- Closing balance = opening balance plus net movement.
The next week’s opening balance is the previous week’s closing balance. Keep an assumptions note beside unusual items so another person can understand the sheet.
Read the lowest week, not just the final total
Here is a fictional four-week extract from a longer forecast. It is an illustration, not an Any Guru customer result. All amounts are pounds; no borrowing is included.
| Line | Week 1 | Week 2 | Week 3 | Week 4 |
|---|---|---|---|---|
| Opening balance | 8,000 | 6,500 | 1,000 | 5,500 |
| Expected receipts | 3,000 | 1,000 | 7,000 | 4,000 |
| Expected payments | 4,500 | 6,500 | 2,500 | 3,000 |
| Net movement | -1,500 | -5,500 | 4,500 | 1,000 |
| Closing balance | 6,500 | 1,000 | 5,500 | 6,500 |
The period ends with £6,500, but week two closes at £1,000. If the owner has chosen a planning buffer of £2,500, that week needs attention. The buffer is an illustrative management choice, not a standard reserve everyone should use.
Weekly totals also have a limit. If a large payment leaves on Tuesday and a receipt clears on Friday, the week-end figure can hide a midweek gap. Expand the vulnerable week into daily movements. The Scottish Government’s forecasting guide also recommends comparing forecasts with actual amounts and updating them as circumstances change.
Test a delay you could realistically face
Make a copy of the base forecast and change one meaningful assumption. In the example, suppose the £7,000 receipt in week three is one invoice and arrives in week five instead. Leave the planned payments unchanged.
Week three would close at minus £1,500, and week four at minus £500. Those are modelled shortfalls, not approved borrowing or proof that a bank will cover them. The exercise shows exactly which receipt needs checking and when the decision becomes urgent.
Do not fix the scenario by silently moving a supplier payment. Discuss any proposed change and record an agreement before treating it as a reliable assumption. The Small Business Commissioner’s guidance points businesses facing payment difficulties towards early conversations and relevant support.
Turn the forecast into a weekly conversation
Set a regular review with whoever owns invoicing, spending and the bank position. A small business can keep it short:
- Replace the completed week’s estimates with actual movements and reconcile the closing balance.
- Explain significant differences: was the amount wrong, the timing wrong or something missing?
- Recheck the most important uncertain receipts and imminent commitments.
- Roll the view forward by one week, adding a new week at the end.
- Record one action, one owner and one due date for each material gap.
A useful action log might say: “Accounts lead to confirm whether the invoice has been accepted and obtain an expected payment date by Thursday.” “Chase cash” leaves too much unclear.
Keep a dated copy of the previous forecast. Over time, repeated timing errors can reveal an invoicing handover problem or an unreliable assumption. Treat that as something to improve, rather than making the spreadsheet appear more accurate after the event.
Know when planning needs professional help
If the business may be unable to meet obligations when due, seek qualified advice promptly. A spreadsheet cannot determine whether continuing to trade, borrowing or changing creditor payments is appropriate. Limited-company directors can start with the official options when a company is insolvent, then discuss their circumstances with a qualified adviser. Sole traders and partnerships need advice suited to their own position.
For the next review, bring five answers: your lowest projected balance, its date, the receipt most likely to move, the payment you cannot overlook, and the action already assigned. That turns a forecast into a practical early-warning habit.
For the wider planning picture, read Financial Forecasting Methods and How to Forecast Monthly Revenue. The weekly cash view adds the detail needed to examine when money becomes available.









