Cash Flow Calculator
Free cash flow calculator: enter opening cash, monthly inflows, and outflows to see net cash flow, closing cash, and a three-month projection instantly.
Bank balance at the start of the month.
Cash actually collected this month, not revenue booked.
Refunds, interest, financing, or asset sales.
Software, marketing, inventory, loan payments, taxes.
Results
Total inflows
$65,000
- Total outflows
- $55,000
- Net cash flow
- $10,000
- Closing cash
- $90,000
- Projected cash in 3 monthsAssumes this month’s inflows and outflows repeat.
- $110,000
You are cash-flow positive by $10,000 this month - if the pattern holds, $80,000 grows to $110,000 within three months.
Free and instant - nothing is stored or sent. Estimates for planning purposes, not accounting, tax, or investment advice.
Profit is an opinion; cash is a fact. A business can post profitable months on the P&L and still miss payroll because the cash arrived later than the revenue was booked. This calculator works entirely in cash: what came in, what went out, and where the bank balance lands.
Enter your opening balance and this month’s expected inflows and outflows. You get net cash flow, the closing balance, and a simple three-month projection that assumes the month repeats - a fast early-warning check before you build a full 13-week forecast.
What cash flow measures (and how it differs from profit)
Net cash flow is total cash in minus total cash out over a period - nothing more. It differs from profit because of timing: revenue you invoiced but have not collected, bills you received but have not paid, and non-cash items like depreciation all appear on the P&L but not in the bank.
That timing gap is why fast-growing businesses are often the most cash-strapped: every new sale adds receivables and inventory before it adds cash.
The math, in plain language
Net cash flow = (cash from sales + other inflows) − (payroll + rent + other outflows). Closing cash = opening cash + net cash flow. The three-month projection is opening cash + 3 × net cash flow - a straight-line extrapolation that assumes this month is typical.
With the defaults - $80,000 opening, $65,000 of inflows, $55,000 of outflows - net cash flow is +$10,000, closing cash is $90,000, and the three-month projection lands at $110,000.
How to interpret the result
Positive net cash flow that persists month after month is the strongest simple signal of financial health. A single negative month is normal - tax payments, annual insurance, inventory builds - but two or three consecutive negative months with no planned cause is a trend that deserves a full forecast.
When the projection turns negative within three months, act on the fastest levers first: invoice immediately, chase overdue receivables, and defer discretionary spending. A rolling 13-week cash flow forecast (see the related guide) is the natural next step.
Frequently asked questions
What is the difference between cash flow and profit?
Profit is revenue earned minus expenses incurred, regardless of when money moves. Cash flow is money actually received minus money actually paid. A profitable business with slow-paying customers can run out of cash; an unprofitable one with big prepayments can look flush for months.
Should I use booked revenue or collected cash for inflows?
Collected cash only. The whole point of a cash flow view is to strip out timing optimism. If you invoice $60,000 but historically collect in 45 days, this month’s inflow is whatever actually clears the bank this month.
How accurate is the three-month projection?
It is a straight-line extrapolation - useful as an early warning, not a plan. It assumes this month repeats exactly, so it misses seasonality, one-time items, and growth. If the projection looks tight, graduate to a proper 13-week cash flow forecast with week-by-week timing.
How much cash should a small business keep in reserve?
A commonly cited target is three to six months of operating expenses in accessible reserves. Businesses with lumpy revenue, concentrated customers, or long collection cycles sit at the high end; steady subscription businesses can operate closer to the low end.
Keep going
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