Cash Flow Calculator

Cash Flow Calculator

Profit doesn’t pay the bills; cash does. Project your bank balance month by month from your opening cash, regular money in and money out, and expected growth, and see straight away if and when you might run short.

Month-by-month forecastGrowth ratesShortfall warningLast updated: November 3, 2026

Forecast your cash flow

Sales receipts actually collected, other income
Suppliers, wages, rent, loan repayments, tax
%
%
months

How the forecast works

Each month

Net cash flow = cash in − cash out  ·  Closing balance = opening balance + net cash flow

The closing balance becomes next month’s opening balance. Cash in and cash out grow by your monthly percentages (use negative numbers for a decline).

Runway

Months of runway = current cash ÷ average monthly net outflow

If you are burning cash, the calculator shows the month your balance first goes below zero.

Profit vs cash flow

A profitable business can still run out of cash. Customers may pay invoices 30–90 days late, stock has to be bought before it’s sold, and loan repayments and tax bills come out of cash but don’t all appear as expenses. That’s why lenders and investors ask for a cash flow forecast, not just a profit forecast.

How to improve cash flow

  • Invoice immediately and shorten payment terms; offer a small discount for early payment.
  • Chase late payers on a fixed schedule.
  • Negotiate longer terms with your own suppliers.
  • Keep stock lean so cash isn’t tied up on shelves.
  • Arrange a credit line early, before you need it.

Frequently asked questions

How do I calculate cash flow?

Subtract the cash leaving the business from the cash coming in over a period. Add the result to your opening balance to get the closing balance.

What is negative cash flow?

When more cash goes out than comes in during a period. It’s normal occasionally (for example, when buying stock), but sustained negative cash flow will eventually empty the bank account.

How far ahead should I forecast?

At least 12 months, updated every month, with a more detailed 13-week forecast if cash is tight.

Net Profit CalculatorProfit, not cash Business Loan CalculatorRepayments Break-even CalculatorSales to cover costs

A forecast is only as good as its inputs. Update it regularly with real figures.

Scroll to Top