Cash Flow Calculator — Methodology

Step-by-step calculation

Project monthly cash flow over 12 months from income and expense estimates, with a chart that flags negative balance months.

1. 1

   Enter your opening cash balance

   Bank + liquid assets at the start of month 1.

2. 2

   Fill in each month's income

   Estimated revenue or cash receipts for each of the 12 months ahead.

3. 3

   Fill in each month's expenses

   Estimated total cash outflows — salaries, rent, software, supplier payments.

4. 4

   Read net cash flow and running balance

   Each month shows net flow (green positive, red negative) and the running balance. The chart highlights any month where cash goes negative.

Assumptions and overrides

Standard cash-flow projection: running balance = opening cash + cumulative (income − expenses). Inputs are estimates; actual cash flow depends on timing of customer payments and supplier terms.

Every region default on the calculator is editable. If your effective rate, fee, or threshold differs from the headline figure shown, type your own number into the field — the calculator recomputes instantly without leaving this page.

Review cadence and corrections

This methodology and the underlying rate defaults are reviewed at least annually, and immediately following any change to the headline rate from IRS, HMRC, or SARS. Every substantive update is recorded on the public changelog. Spotted an error? See the corrections policy for how to report it.

See the full editorial policy for the standards every page on BusCalcTools is held to.