Cash Flow Projection Calculator
Project monthly business cash flow over 12 months.
What this calculator does
This cash flow projection calculator maps twelve months of money in and money out. Enter your current monthly revenue, monthly expenses, and an expected monthly growth rate, and it returns projected annual revenue, annual net cash flow, and a month-by-month table showing revenue, expenses, and the net position for each period.
The value is in the shape rather than the total. A single annual figure can conceal a two-month trough in the middle of the year that would empty the bank account. Reading the schedule month by month shows where the pressure points fall and how much cushion you need to get past them.
When to use it
Use it before any commitment that changes your fixed cost base — a hire, a lease, a piece of equipment on finance. Adding the new cost to the expense line and rerunning the projection shows whether the business absorbs it comfortably or only survives it in the strongest months.
It is also the document lenders and investors expect to see, and building it yourself rather than having your accountant produce it means you understand its assumptions well enough to defend them. Just as importantly, it is the tool for deciding not to spend — a projection that goes negative in month seven is a clear argument for deferring a hire until month nine.
Understanding the inputs
Monthly revenue should be cash you expect to collect, not invoices you expect to issue. If customers typically pay in 45 days, the revenue belonging in a given month is what was sold roughly six weeks earlier.
Monthly expenses should include everything that leaves the account: payroll and payroll taxes, rent, software, loan principal as well as interest, and a realistic allowance for the irregular costs that always appear. Growth rate is applied monthly and compounds, so treat it carefully — 3 percent monthly is about 43 percent annually, which is a demanding pace to sustain for a full year.
How is this calculated?
Monthly Net Cash = Revenue − Expenses. Ending Balance = Starting + Net Cash. Revenue grows at specified rate each month.
A worked example
A business currently books $85,000 a month against $78,000 in expenses, growing 3 percent monthly. Month one nets $7,000. By month twelve revenue reaches about $117,700 and the monthly net is close to $39,700. Across the year, revenue totals roughly $1.21 million against $936,000 of expenses, leaving around $270,000 of net cash flow.
That headline looks comfortable, but the first quarter generates only about $23,000 combined. If a $40,000 equipment purchase lands in month two, the business is short despite finishing the year strongly. Halving the growth rate to 1.5 percent monthly cuts annual net cash flow to roughly $175,000 — which is the case worth planning against.
Limitations and assumptions
The model applies a constant growth rate and flat expenses, neither of which survives contact with a real business. It has no seasonality, so a retailer earning 40 percent of revenue in the fourth quarter will find it badly misleading. Expenses also step upward with growth rather than staying level.
Most importantly, it does not model payment timing. Revenue is treated as collected in the month it is earned, which is the exact assumption that causes profitable businesses to run out of money. If you invoice on terms, adjust the revenue line to reflect actual collection, and pair this annual view with a rolling thirteen-week cash forecast.
Common Questions
- Why is cash flow different from profit?
- Profit is an accounting measure recorded when a sale is made. Cash flow records when money actually moves. A business that invoices $100,000 in March on 60-day terms books the profit in March but sees nothing until May. Payroll, meanwhile, is due every two weeks regardless.
- How many months should I project?
- Twelve months for planning and thirteen weeks for survival. The annual view supports hiring and investment decisions; the weekly view is what you need when cash is tight, because a monthly model can show a positive month while hiding a payroll you cannot meet on the fifteenth.
- What growth rate should I assume?
- Whatever your last six months actually delivered, not what your plan says. Three percent monthly compounds to roughly 43 percent annually, which is aggressive for an established business and modest for an early-stage one. Run a pessimistic case at half your assumed rate — that is the one worth planning around.
- What is the most common mistake in a cash flow forecast?
- Assuming customers pay on time. Treating invoices as cash on the day they are issued removes the entire problem the forecast exists to reveal. Build in your actual average collection period, and if it is 45 days, model it as 45 days rather than the 30 written on the invoice.
- Should the forecast include loan repayments and taxes?
- Yes, both, in the month they leave the account. Debt principal is not an expense on the income statement but is very much a cash outflow. Quarterly estimated taxes and any annual insurance renewal are the lumpy items that most often turn a comfortable-looking forecast into an overdraft.
- How much cash buffer should a business hold?
- Three to six months of operating expenses is the common guideline for an established business, and startups burning cash typically want twelve to eighteen months of runway. Businesses with seasonal revenue or long payment terms should sit at the top of those ranges rather than the middle.
- Can a profitable business run out of cash?
- Routinely, and rapid growth is the usual cause. Growth means buying inventory and paying staff before customers pay you, so the faster you grow the wider the gap becomes. More companies fail while profitable and growing than fail while unprofitable and shrinking.
- How do I improve cash flow without increasing sales?
- Shorten the gap between paying and being paid. Invoice on delivery rather than month end, take deposits on large orders, offer a small early-payment discount, negotiate longer supplier terms, and chase overdue invoices systematically. Ten days off average collection frees up roughly a third of a month's revenue permanently.
- What should I do when the projection turns negative?
- Act on it while the negative month is still several months out, since that is when you have options. A line of credit is far easier to arrange when you do not yet need it. Waiting until the month arrives reduces the choice to emergency measures at the worst possible price.
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