In short
- Profit counts what is invoiced; cash, what is collected and paid.
- Enter each receipt and payment in the week it actually happens.
- What matters is the lowest balance, not the one at the end of the period.
Why profit is not enough
A business can make money on paper and still run out of cash. Profit counts sales when they are invoiced; cash, when they are collected. If you collect in 60 days and pay in 30, every sale makes you advance money. A cash flow forecast tells you when cash will run short, in time to act.
How to build one
- Start from today's balance in the bank.
- Enter each receipt in the week you expect to receive it, not the week you invoice.
- Enter each payment in the week it is due: payroll, suppliers, rent, taxes, loan payments.
- Add and subtract week by week and look for the lowest balance.
A 13-week horizon (one quarter) is common: long enough to see problems coming and short enough for the figures to be reliable.
A worked example
Example calculated with our calculator
| Opening balance | €8,000 |
| Week 1: you collect €3,000 and pay €2,000 | €9,000 |
| Week 2: you collect €1,000 and pay €9,000 (payroll and taxes) | €1,000 |
| Week 3: you collect €6,000 and pay €1,500 | €5,500 |
| Week 4: you collect €2,000 and pay €2,500 | €5,000 |
| Critical point | Week 2, at €1,000 |
The month ends with €5,000, but in week 2 the account almost empties. If you want to keep a €3,000 cushion at all times, you would be €2,000 short that week.
What to do if you see a gap
- Bring receipts forward: invoice sooner, ask for deposits or chase overdue invoices.
- Move payments: agree a one-off delay with suppliers.
- Arrange financing in advance: a credit line is easier to negotiate before you need it.
Watch out: be cautious with receipts. If a customer usually pays late, put the payment in the week they actually tend to pay.
Work it out with your numbers
The calculator gives you the balance week by week for 13 weeks, the lowest point and the money you would need to stay above your minimum.
Sources and review. Our own calculation with the Numveria cash flow forecast calculator. This guide does not cite external data. Reviewed on 3 November 2026.