Using the Cash Flow Forecast
Enter your expected weekly income and regular expenses. Red rows show weeks where your bank balance goes negative — a warning sign to act before it happens.
Tips for Accurate Forecasting
Income: Be conservative. If you expect $4,000 but clients sometimes pay late, use $3,000–$3,500. The point of forecasting is to spot problems early.
Tax reserve: The calculator sets aside the % you specify from income each week into an imaginary "tax account." This models the good habit of ring-fencing tax money as it arrives. 25–30% is typical for a GST-registered sole trader.
Large payments: Use these fields for known one-off outgoings — an IRD provisional tax instalment, vehicle registration, annual insurance premium, or a large materials order.
Warning Signs to Watch
- Negative balance weeks — you'll need overdraft, a credit card, or to bring forward an invoice
- Closing balance below 1 month expenses — insufficient buffer for unexpected delays
- Tax reserve lower than expected IRD bill — increase the reserve % immediately
Building a Cash Buffer
Aim for a minimum 4-week buffer in your business account (4 × total weekly expenses). This absorbs a bad week, a slow client, or an unexpected cost without causing a crisis.
Use our Job Cost Calculator to check whether individual jobs are contributing enough margin to fund this buffer.