By Eddy Hood, Founding Partner, Ignite Spot Accounting
I've watched business owners manage cash by checking their bank accounts and doing mental math. They remember payroll, think through which customers should pay soon, subtract a few bills, and decide there's enough room to move forward.
I understand the appeal. You're busy, and you know your business. But a tax payment, an annual renewal, or a late customer can change that picture quickly. As the company grows, keeping it all in your head becomes harder.
Managing cash requires a system you can review and update. A 13-week cash flow forecast estimates the cash your business expects to receive and pay each week for the next 13 weeks. You update it weekly and add another future week, keeping a rolling view of your cash position.
I want you to be able to test a decision before you commit your money. A written forecast gives you somewhere to do that.
Thirteen weeks gives you roughly a quarter of visibility. Weekly detail helps you see payroll, collections, rent, and tax payments collide, connecting commitments to specific dates.
Your profit-and-loss statement explains revenue and expenses over a period. On an accrual basis, those amounts can appear before money changes hands. An annual budget sets broader financial expectations. Your weekly cash flow forecast answers a more immediate question: when will money be available to pay what we've committed?
I've explained why profit and cash differ in the previous article. Forecasting takes the next step: planning for the timing gap.
Start by gathering bank activity, unpaid customer invoices, unpaid bills, and your payroll calendar.
I would organize every forecast around five elements. Use weekly columns with real dates, and put money in the week it should move.
Start with cash available across business bank accounts. Identify restricted funds separately. Account for outstanding checks and initiated payments, but count each obligation once: either adjust starting cash or include its future clearance as an outflow.
An undrawn credit line isn't cash. Keep available financing separate.
List customer payments by expected collection date. An agency's signed contract or issued invoice doesn't fund payroll until the payment arrives. Use payment history, billing requirements, disputes, and customer conversations to choose realistic dates.
Include other expected receipts separately, such as refunds or confirmed funding. Keep uncertain new sales clearly identified rather than treating your pipeline as money already collected.
Use payroll funding dates. Include wages, employer payroll taxes, benefits, and retirement contributions, with separate payment dates where needed. If your payroll provider withdraws several items together, don't add those same amounts again elsewhere.
Include vendors, contractors, rent, insurance, software, taxes, debt principal and interest, equipment, and planned owner distributions. Review automatic withdrawals and annual renewals. Include cash purchases even when accounting spreads their expense over time.
Beginning cash + cash received − cash paid = ending cash.
One week's ending cash becomes the next week's beginning cash. Link those cells so changing a payment updates every later week.
Enter known obligations first, then add receipts using realistic collection dates.
A delayed collection can reduce available cash even when sales stay the same. Here are three weeks for a hypothetical service business, not an Ignite Spot client:
| Cash flow | Week 1 | Week 2 | Week 3 |
|---|---|---|---|
| Beginning cash | $80,000 | $75,000 | $85,000 |
| Customer collections | $45,000 | $60,000 | $40,000 |
| Cash payments | $50,000 | $50,000 | $45,000 |
| Ending cash | $75,000 | $85,000 | $80,000 |
Week 1's $50,000 in payments includes $30,000 in payroll and $20,000 in other scheduled payments. The calculation is $80,000 + $45,000 − $50,000 = $75,000. That $75,000 becomes Week 2's beginning cash. The full forecast continues the same way through Week 13.
Now suppose $25,000 of Week 1's collections arrives in Week 2 instead. Week 1's collections fall to $20,000, and ending cash falls to $50,000.
Week 2 then starts with $50,000 and receives $85,000: its original $60,000 plus the delayed $25,000. With payments unchanged at $50,000, it still ends with $85,000. Week 3 stays unchanged. The receipt moved; it wasn't lost.
That temporary dip matters. Seeing it early gives you time to follow up on collections, reconsider optional spending, or discuss financing. Try moving one significant receipt back a week in your own forecast and inspect the affected balances.
Change the assumptions behind a decision and compare the resulting cash balances. A forecast becomes useful when you can push and pull those levers.
Hiring: Add recruiting, equipment, wages, taxes, benefits, and training costs. Model when the employee starts contributing billable work and when customers will pay for it. Hiring two people next month means funding both before assuming their work produces collected cash.
Purchases and collections: Move a discretionary equipment purchase to a later week. Separately, test faster collections supported by specific actions, such as resolving invoice disputes. Don't assume customers will pay early simply because you need them to.
Locations and launches: Add deposits, setup costs, marketing, overlapping overhead, and delayed receipts. For a 15% revenue decline, translate the lower sales into collections using your billing cycle; some costs may change too. Extend the model beyond 13 weeks when the commitment lasts longer.
Before approving spending, compare the scenarios' lowest cash balances, not just where you finish Week 13.
Your cash cushion should reflect your obligations and specific risks. I don't think one percentage fits every business.
My personal rule of thumb is this: “I really do believe projects take three times as long and cost three times as much as we think they will.”
That's a deliberately cautious philosophy, not a research-backed statistic or an instruction to triple every budget. It's a reminder to challenge optimistic assumptions. A new location's budget might include construction but miss overlapping rent. A launch might include marketing but overlook months of payroll before customers pay.
Build a base case with reasonable expectations, a downside case with plausible overruns or delays, and a severe-downside case combining significant risks. Model costs arriving sooner and revenue arriving later.
Then set a minimum cash balance around essential payments, customer concentration, collection volatility, and the time needed to adjust spending or arrange funding. Compare each scenario's lowest balance with that floor. Include contingencies explicitly; don't hide them in several rows and count them twice.
Write down your minimum balance and the risks behind it before deciding how much to commit.
Update your cash flow forecast every week, and more frequently when cash is tight or circumstances change quickly. Give the process a named owner and a recurring appointment.
Regular comparisons help you improve assumptions instead of repeating the same optimistic collection dates. Accurate records matter here; our bookkeeping and CFO services connect financial reporting with forward-looking planning.
End each review with the lowest projected cash balance, its week, and the decision it requires.
Use 30 minutes to build a first pass, with your records ready. A more complicated business may need additional setup time.
Create 13 weekly spreadsheet columns. Add rows for beginning cash, expected collections, other receipts, payroll, vendor payments, rent and overhead, taxes and debt payments, other planned cash activity, and ending cash. Add formulas and enter your best-supported estimates.
Duplicate the forecast and test these changes individually:
For each scenario, find the lowest projected cash balance and compare it with your minimum cushion. Then combine risks that could reasonably happen together.
Identify one change to protect your cash, with an owner and deadline.
Show planned borrowing and repayments separately. Include a draw only when availability and timing are realistic, along with interest and fees. An unused limit belongs in your financing notes, not beginning cash.
Keep speculative receipts separate from dependable collections. Test winning and losing a major contract individually. A probability-weighted portion of one large sale can suggest cash you'll never receive if that deal falls through.
Yes. Friday's receipt can't fund Tuesday's payroll. Check daily timing in tight weeks and allow for bank processing and payroll funding deadlines.
I don't expect you to predict the future perfectly. Customers will change their plans, projects will take unexpected turns, and some weeks will look different from what you put in the spreadsheet.
What I want is for you to make financial decisions with your eyes open. Before you hire, expand, or commit to a major purchase, you should be able to see what it could mean for the cash your business needs.
Start with a simple forecast and keep coming back to it. You'll have a place to work through the uncertainty instead of carrying every estimate in your head.
If you'd like someone to think through those decisions with you, I'd welcome the conversation. Explore our fractional CFO services to see how we can help with cash forecasting, budgeting, and the next step you're considering.