Cash flow forecasting: how small businesses see next month's money before it runs out

Cash flow forecasting is the habit of looking at your bank balance not as it is today, but as it will be in four, eight, or thirteen weeks' time. Most small businesses that run out of money were profitable on paper — they simply ran out of cash on a Tuesday when payroll, rent, and a supplier payment all landed in the same week. A forecast doesn't need a finance degree or expensive software. It needs your real invoices, your real bills, and an honest look at when money actually moves.

Cash flow forecasting: start with what you know

A cash flow forecast has three ingredients, and you already have all of them.

Opening cash. Your actual bank balance today, across every account the business uses. Not the balance your accounting software shows — the balance the bank shows. Reconcile first; a forecast built on a wrong starting number is wrong in every week that follows.

Money coming in. List every customer invoice that is still unpaid, with its due date and amount. Then be honest about when each one will actually be paid. A customer who always pays two weeks late should be forecast two weeks late, not on the due date. Add any other expected receipts: recurring subscriptions, deposits for upcoming work, tax refunds you are genuinely expecting. Leave out anything that is only a hope — a deal that hasn't been signed is not a receipt.

Money going out. This is the part people underestimate. List payroll and the taxes that go with it, rent, utilities, supplier invoices already received, loan repayments, and subscriptions. Lease payments belong here too — under IFRS 16 Leases, a lease is a real liability with real monthly cash going out, not just a line in the notes. Then add the irregular items: the annual insurance premium, the quarterly tax payment, the vehicle service you know is coming. The surprises in cash flow are almost always the outgoings you forgot, not the income that failed to arrive.

Cash flow forecasting: the 13-week rolling forecast

The most useful format for a small business is a 13-week rolling forecast — one row per week, with columns for opening balance, receipts, payments, and closing balance. Thirteen weeks is long enough to see trouble coming and short enough that the numbers are mostly real rather than guessed.

Build it in a spreadsheet. Week one uses invoices and bills that already exist, so it is nearly exact. Weeks two to four are mostly real too. Beyond that you are estimating, and that is fine — the point is the shape of the curve, not precision to the last dollar. If the closing balance dips below zero in week nine, you have nine weeks to fix it. Without a forecast, you find out in week nine.

Update it every week. A forecast that is never refreshed is a photograph, not a forecast. Roll it forward: drop the week that just passed, add a new week at the end, and replace estimates with actuals. The whole job takes thirty minutes once the template exists, and it is the single most valuable half hour in a small business owner's week.

Cash flow forecasting: what to do when the forecast turns red

A forecast that shows a shortfall is not bad news — it is early news. You have options, and each one is cheaper the earlier you act.

Pull receipts forward. Chase overdue invoices now, not when the balance is already low. Offer a small early-payment discount to the customers who can pay sooner. Invoice work the day it is done, not at month end — every day of delay is a day your forecast slips.

Push payments out — honestly. Ask a supplier for an extra two weeks before you are late, not after. Renegotiate a subscription you barely use. Delay a purchase that is a want, not a need. None of this is hiding from your obligations; it is sequencing them so the business survives the tight weeks.

Bridge the gap deliberately. If the shortfall is real and temporary, a short-term overdraft or credit line arranged while the balance is still healthy costs far less than emergency borrowing when the account is already empty. Banks lend to businesses that plan; they charge a premium to businesses that panic.

Cut with a scalpel, not an axe. A forecast shows exactly which weeks are tight and by how much. That lets you trim a specific cost in a specific week instead of cutting everything in a panic and damaging the business you are trying to save.

Cash flow forecasting: the mistakes that break it

The most common mistake is forecasting profit instead of cash. A sale is not cash until the customer pays, and an expense is not cash until you pay it. A forecast built from your profit and loss statement will tell you the business is fine right up until the bank says otherwise.

The second mistake is optimism in the receipts column. Forecast your customers as they actually pay, not as their terms say they should. If your average collection time is 45 days, forecast 45 days. Hoping for 30 does not make it 30 — it just moves the surprise closer.

The third mistake is forgetting the taxman. VAT, sales tax, payroll taxes, and income tax instalments are all cash outflows with fixed dates, and they are large enough to sink a forecast that ignored them. Put every known tax date in the forecast the moment you know it.

The fourth mistake is building it once and never looking at it again. A forecast is a routine, not a project. The businesses that survive tight periods are the ones that looked at the numbers every week and acted while they still had choices.

Cash flow forecasting: keep it simple, keep it weekly

You don't need a finance team to forecast cash flow. You need a spreadsheet, your bank balance, your unpaid invoices, and your unpaid bills — and thirty minutes a week. Start with thirteen weeks, update it every week, and act on what it shows while you still have time to act.

If you'd like the tools that make this easier — invoicing that tracks who owes you, and reports that show where your money actually goes — join the waitlist at tetramlabs.com. Point is built for small businesses that want to see their money clearly, and we're opening it to a small group of early users first.