# Cash flow calculator > Put in the cash in the bank today and what comes in and goes out each month. You get the month cash runs short, and a chart of every month until then. Free, no sign-up. The math runs in the browser at https://1610advisory.com/tools/cash-flow-calculator; nothing typed is sent or saved. ## Inputs - **Cash in the bank today.** All business accounts, as of today. - **Money in each month.** Customer payments and any other deposits. - **Money out each month.** Payroll, rent, bills, loan payments, owner draws. - Optional: monthly growth for money in and money out, in percent a month. ## The math Each month: cash at month end = cash at the start + money in - money out. The month cash runs short is the first month the balance ends below zero, counted from the current month. Months of cash is the number of full months covered, the current month included. ## How to read the result The calculator starts with the cash in your bank account today. Each month it adds what comes in and takes out what goes out. The first month the balance would end below zero is the month cash runs short. Months of cash counts the full months your cash covers, this month included. If money in is equal to or more than money out, cash does not run short, and the chart shows how it builds. Net cash flow is money in minus money out for the month. When it is negative, that gap is your burn: the amount the bank balance falls each month. Use cash, not the P&L. A sale you have invoiced but not collected (accounts receivable) is not cash until it lands. Loan payments, owner distributions and equipment purchases are cash out, even though some of them never show up as expenses on the P&L. ## What to do when cash runs short - **Check the inputs.** Pull the last three months of bank statements and average the deposits and the withdrawals. A guess about money out is usually low. - **Collect faster.** Look at accounts receivable: invoices out, not yet paid. Bill sooner, follow up sooner, and ask for deposits on big jobs. - **Pay on purpose.** Know which bills are fixed and which can move. Talk to a vendor before a bill is late, not after. - **Fix the gap before you borrow.** A line of credit buys time. It does not fix a month where more goes out than comes in. - **Run it again.** Change money in or money out to match the plan and watch the month move. Then talk to your banker early, while you still have choices. This is a straight-line estimate. Real months are lumpy: seasons, annual bills, tax payments, a big customer who pays late. A cash flow forecast built from your books follows all of that. ## Questions ### How do I calculate cash flow? Cash flow for a month is the money that came in minus the money that went out. Start with the cash in the bank, add what comes in, take out what goes out, and you have the balance at the end of the month. This calculator repeats that for every month ahead. ### What is cash runway? Runway is how long your cash lasts if money in and money out stay where they are. When you spend more than you take in, divide the cash in the bank by the monthly gap. The calculator does the same math month by month and names the month the money runs out. ### What should I put in money in and money out? Use cash, not the P&L. Money in is what lands in the bank: customer payments, loan proceeds, any other deposit. Money out is everything that leaves: payroll, rent, vendors, loan payments, taxes and owner draws. Your last three months of bank statements are the easiest place to start. ### When should I add monthly growth? When money in or money out moves in a steady direction. If sales grow each month, or a new hire raises payroll, a growth rate gets closer than a flat number. Use a minus sign for money that is falling. ### Is my information saved? No. The math runs in your browser. Nothing you type is sent to us or saved, and there is no sign-up. ### Is this a cash flow forecast? It is a quick estimate. A real forecast follows your actual bills, payroll dates, how fast customers pay and your seasons, often week by week. If the answer here worries you, that is a good time to build one. ## Book a Walkthrough A free 30-minute walk through your numbers. Send the last two years of P&Ls and a balance sheet first, and you leave with what we see and what we'd recommend. - **Send the books first.** The last two years of P&Ls and a current balance sheet. That's enough for us to walk in with something real, not a blank page. - **Goals first.** We talk about the business, what you're building toward, and how it feels from where you sit. The numbers only mean something against that. - **You leave with our read.** One or two things we see in your numbers, and what we'd do about them. Yours to run with, or to hire us for. - **We'll be honest.** If we're not the right fit, we'll say so. We'd rather tell you that than sell you a seat you don't need. Book one at https://1610advisory.com/contact.