Why 13 weeks
Most owners already have a profit-and-loss statement, produced monthly, usually well after the month has closed. That tells you whether the business is profitable. It does not tell you whether you can pay salaries in three weeks, and by the time an accountant produces the monthly figures, a cash problem that started small has often already grown.
Thirteen weeks is a quarter — long enough to see a slow month coming and act before it arrives, short enough that your weekly numbers stay grounded in things you actually know rather than guesses about next year. A 52-week forecast looks impressive but is mostly fiction beyond week eight or so, because you cannot really know your December receipts in January. Thirteen weeks keeps every row honest.
The other advantage of a weekly grain, rather than monthly, is that it catches timing. A business can be profitable for the month and still run out of cash in week two of it, because a large payment lands before a large receipt. Monthly figures smooth that away. Weekly figures show it.
The columns
Keep the structure simple enough that you actually update it every week. A single spreadsheet, one column per week, with these rows:
- Opening cash — your actual bank balance at the start of the week. This is a fact, not an estimate; check it against the bank.
- Receipts, broken down by customer or type — separate rows for your largest few customers or income streams, and one row for everything smaller, grouped. Seeing "Customer A" as its own line matters more than most owners expect, because a single late payer can explain most of a dip.
- Payments, broken down by category — payroll, MPF contributions, rent, suppliers, loan repayments, tax instalments, and a line for everything else. Include MPF and rent as their own rows specifically, because they are fixed, recurring, and unforgiving if missed.
- Closing cash — opening cash, plus receipts, minus payments. This becomes next week's opening cash.
Resist the urge to add more detail than this. A forecast with forty rows is one that stops getting updated by week three.
Updating it every Monday in 20 minutes
The forecast is only useful if it is current, and it only stays current if updating it is quick. A workable Monday routine:
- Enter last week's actual receipts and payments in place of what you had estimated.
- Confirm this week's opening cash against the bank balance.
- Update the estimates for the next few weeks based on anything you now know — a customer has confirmed a payment date, a supplier invoice has come in, a large expense is now certain rather than assumed.
- Extend the forecast by adding a new week 13 at the end, so it always looks 13 weeks ahead.
Twenty minutes is realistic once the spreadsheet exists and the habit is set. The first one you build will take longer, mostly because you are gathering numbers you have not previously had in one place.
How to read it
The number that matters is not the closing cash at week 13. It is the lowest point anywhere across the thirteen weeks. Owners naturally look at the final column, but a business can end the quarter comfortably while passing through a genuinely dangerous week five or six along the way. Scan every week's closing cash, find the minimum, and treat that number as the one you are managing towards.
Also watch the trend, not just any single week. A forecast that dips once and recovers is a timing issue. A forecast where the closing cash gets a little lower every single week is a structural issue, and it will not fix itself just because next week arrives.
What to do when it dips
If the lowest point in your forecast is uncomfortably close to zero, or below it, you have weeks of notice to act — which is the entire point of building the forecast in the first place.
- Collect earlier. Call your largest outstanding customers before the payment is overdue, not after. A short, direct conversation moves more invoices than a second reminder email.
- Negotiate terms. Ask suppliers for a few extra days, or ask a large customer whether a deposit or milestone payment is possible instead of waiting for full payment at completion.
- Delay discretionary spend. Anything that is not payroll, rent, MPF, or a contractual obligation can usually move a few weeks without real damage. Decide which items those are before you need to, not while you are under pressure.
- Talk to the bank early. If the dip is real and unavoidable, a conversation with your bank while you still have weeks of runway is a completely different conversation from one you have the week you run out. Lenders respond far better to a business that saw a problem coming than to one asking for help after the fact.
The forecast does not solve a cash problem on its own. What it does is give you enough warning to solve it while your options are still good ones.