A cash flow forecast helps you answer a practical question before it becomes urgent: will the business have enough cash to cover upcoming commitments? This guide provides a reusable monthly cash flow forecast template, a 13-week view for closer planning, simple formulas, worked examples, and a review routine for invoices, bills, taxes, payroll, and irregular costs.
Overview
Cash flow forecasting is the process of estimating when money will enter and leave your business. It is different from a profit report. A business can show a profit on paper and still experience a cash shortage if customers pay late, large bills are due before sales are collected, or cash is tied up in inventory and equipment.
A useful small business cash flow forecast does not need to predict the future perfectly. Its purpose is to make timing visible, identify pressure points, and give you time to choose an appropriate response. You might follow up on overdue invoices, delay a nonessential purchase, adjust a payment schedule, or revise a sales target.
Use two views together:
- Monthly forecast: a broader view for budgeting, recurring commitments, tax planning, and decisions over several months.
- 13-week forecast: a shorter, more detailed view for monitoring near-term receipts and payments.
Keep the forecast separate from your bank reconciliation. The reconciliation records what happened. The forecast estimates what is likely to happen next and should be updated as actual figures become available.
How to estimate cash flow
Start with the cash balance available at the beginning of the period. Then list expected cash receipts and cash payments in the period they are likely to reach or leave the bank account—not necessarily when an invoice is issued or a bill is received.
The core formulas are:
- Total cash in = customer payments + other receipts
- Total cash out = operating payments + owner payments + taxes + debt or financing payments + planned one-off costs
- Net cash flow = total cash in − total cash out
- Ending cash = opening cash + net cash flow
- Next period opening cash = previous period ending cash
For a monthly cash flow projection template, create columns for each month and rows for the categories below:
| Category | What to record |
|---|---|
| Opening cash | Cash available at the start of the month |
| Customer receipts | Payments expected to arrive during the month |
| Other receipts | Loans, grants, refunds, deposits, or owner contributions |
| Payroll and contractor payments | Expected payment dates and amounts |
| Operating expenses | Rent, software, utilities, insurance, supplies, and other regular costs |
| Taxes and statutory payments | Amounts and due periods set aside for your business |
| Debt and financing | Scheduled principal, interest, or other finance payments |
| Irregular costs | Equipment, repairs, annual renewals, professional fees, or planned purchases |
| Ending cash | Opening cash plus receipts minus payments |
For a 13-week cash flow forecast, replace monthly columns with one column per week. Enter known payment dates where possible. If a customer usually pays within a range rather than on a fixed date, use a conservative expected week and note the assumption. The weekly view is most useful when it shows the lowest projected balance, not just the total for the quarter.
Inputs and assumptions
The quality of a business cash flow spreadsheet depends on the quality of its assumptions. Label each input as either confirmed, probable, or uncertain. This makes it easier to build a cautious version alongside a likely version.
Income assumptions
- List unpaid invoices by customer, amount, expected payment date, and confidence level.
- Separate signed work from sales that are only expected or under discussion.
- Use the payment behavior you actually observe rather than the payment terms alone.
- Exclude sales that have not yet been contracted from the cautious forecast, or place them in a separate upside scenario.
Expense assumptions
- Review bank transactions and supplier records for recurring bills that are easy to overlook.
- Include payroll, contractor invoices, subscriptions, rent, utilities, insurance, loan payments, and owner drawings where relevant.
- Record taxes and other required payments in the period when cash is expected to leave the account.
- Add irregular costs such as annual renewals, equipment replacement, repairs, training, or seasonal stock purchases.
Do not mix sales tax or VAT collected for another party with operating revenue. Track the cash received and the related payment obligation separately so the forecast does not treat temporarily held funds as freely available cash. Because tax treatment and payment schedules vary by location and business structure, confirm the applicable treatment with a qualified adviser.
Include a notes column in the spreadsheet. Useful notes include “awaiting client approval,” “annual renewal,” “payment date confirmed,” and “estimate based on prior bill.” Notes turn the forecast into an operational document rather than a set of unexplained numbers.
Worked examples
Suppose a business begins April with 8,000 in cash. It expects customer receipts of 12,000 and other receipts of 500. Planned cash payments are payroll and contractors of 6,000, operating expenses of 2,700, taxes of 1,200, and an equipment purchase of 900.
The calculation is:
- Total cash in = 12,000 + 500 = 12,500
- Total cash out = 6,000 + 2,700 + 1,200 + 900 = 10,800
- Net cash flow = 12,500 − 10,800 = 1,700
- Ending cash = 8,000 + 1,700 = 9,700
Now test the timing. If 4,000 of customer receipts are delayed into May, April cash in falls to 8,500. Net cash flow becomes negative 2,300, and ending cash falls to 5,700. The business may still be profitable overall, but the forecast highlights a near-term collection problem. That insight supports an action such as confirming the payment date, sending a polite reminder, or reviewing whether the equipment purchase can be rescheduled.
For the 13-week version, divide the same information by expected week. A single month can look comfortable in total while one week shows a low or negative balance. Flag that week and record the action required. Avoid using a projected balance as permission to spend unless the underlying receipts are reasonably dependable.
If pricing or project profitability is part of the problem, review the markup versus margin calculator guide and the hourly rate to project price calculator guide. Better pricing can improve future cash generation, but it does not replace short-term collection and payment planning.
When to recalculate
Review the forecast weekly when cash is tight, receipts are unpredictable, or the business has significant upcoming commitments. A monthly review may be sufficient for a stable business with reliable payment patterns, but update the file whenever a material assumption changes.
At each review:
- Replace the previous period's estimates with actual bank receipts and payments.
- Move unpaid invoices to the date you now expect to collect them and mark overdue items clearly.
- Confirm the next four to thirteen weeks of payroll, supplier bills, taxes, financing, and subscriptions.
- Add new one-off costs and remove commitments that have been cancelled.
- Compare the cautious and likely forecasts, then identify the lowest projected cash balance.
- Assign an owner and deadline to each action, such as invoice follow-up or expense approval.
Recalculate after a large contract is signed, a major customer pays late, staffing changes, prices change, financing is added, or a significant purchase is proposed. Refresh tax-payment examples, category labels, and spreadsheet instructions at least annually so the template reflects your current business and local requirements.
Keep one dated copy of each forecast rather than overwriting the entire history. Comparing forecasts with actual results will show whether your assumptions are too optimistic, whether customers usually pay later than expected, and which expenses are routinely missed. Over time, that feedback makes the template more useful and gives you a clearer basis for decisions.
