Cash flow forecasting tells you whether you'll have enough money to cover your bills next month — before it's too late to do anything about it. Here's how to build a simple, accurate forecast.
What Is Cash Flow Forecasting?
A cash flow forecast predicts how much money will flow in and out of your business over a future period — typically the next 3, 6, or 12 months. Unlike a profit and loss statement (which measures profitability), a cash flow forecast focuses purely on timing: will you actually have money in the bank when you need to pay your bills?
A business can be profitable on paper and still run out of cash. This happens when the timing of inflows and outflows doesn't match — you've invoiced $50,000 but you won't collect it for 60 days, and your payroll is due in two weeks.
Cash flow forecasting is the tool that prevents this from being a surprise.
Why Small Businesses Underestimate Cash Flow Problems
Most business owners understand profit. Fewer understand liquidity — the availability of cash at the right time.
The gap usually comes from:
A forecast doesn't prevent these issues. It warns you about them early enough to act.
How to Build a Simple Cash Flow Forecast
Step 1 — List Your Expected Cash Inflows
For each month in your forecast period, estimate all cash you expect to receive:
Key point: Record when cash is received, not when it's invoiced. If you invoice in January on Net 30 terms, the cash appears in February.
Step 2 — List Your Expected Cash Outflows
Again, record when cash actually leaves your account, not when the liability arises.
Step 3 — Calculate Opening and Closing Balances
Closing Balance = Opening Balance + Inflows − Outflows
The closing balance for one month becomes the opening balance for the next.
Step 4 — Identify Problem Months
Look for months where the closing balance goes negative or falls below a comfortable safety buffer. These are the months you need to plan for now — by accelerating collections, delaying non-essential outflows, or arranging credit facilities.
A Simple Example
| | Jan | Feb | Mar |
|---|---|---|---|
| Opening balance | $8,000 | $5,500 | $2,000 |
| Inflows | $12,000 | $9,500 | $14,000 |
| Outflows | $14,500 | $13,000 | $11,000 |
| Closing balance | $5,500 | $2,000 | $5,000 |
February looks tight. If anything goes wrong — a client pays late, an unexpected expense — February could go negative. Knowing this in January gives you time to chase that slow-paying client or defer a non-urgent purchase.
Tips for More Accurate Forecasts
Be conservative on inflows. If a client sometimes pays late, assume they will. Use your actual collection history rather than your stated payment terms.
Be complete on outflows. It's easy to forget irregular expenses. Go through last year's bank statements and list everything — annual subscriptions, professional fees, vehicle services, equipment maintenance.
Update it regularly. A forecast that hasn't been updated in three months is worse than useless. Aim for weekly updates in the first year; monthly once you have a good feel for your business rhythms.
Run multiple scenarios. What if your biggest client pays 30 days late? What if a major job falls through? Stress-testing your forecast reveals vulnerabilities before they become crises.
Using Your Business Data for Better Forecasts
Quotation Expert's reports give you the historical data to build accurate forecasts: monthly revenue, collections by period, payroll costs, bills, and expenses — all in one place. The more accurate your historical data, the more accurate your forecast.
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