Cash flow forecasting vs. AR forecasting: what's the difference and why it matters

Finance teams often use "cash flow forecasting" and "AR forecasting" interchangeably. They're not the same thing, and the difference has real implications for how you build your finance stack and which metric to optimise for.

Why AR forecasting is the foundation

Cash flow forecasting is only as good as its AR inputs. Most CFOs forecast AR receipts using simple assumptions: "all net-30 invoices pay in 30 days." In reality, if your average customer pays in 42 days, every cash forecast is systematically off by 12 days — which at $5M ARR represents roughly $165,000 in cash that isn't where you thought it would be.

AR forecasting — predicting when specific invoices will actually be paid based on customer history — feeds accurate inputs into cash flow models. Courtasy builds per-customer payment probability models that produce realistic AR receipts forecasts, not just invoice due dates.

Which one do you need first?

Both — but in order. Start with AR forecasting. Get visibility into when your outstanding invoices will actually be paid. Then feed that data into a cash flow model.

If you're still forecasting AR using invoice due dates instead of predicted payment dates, your cash flow forecast will always be off. Courtasy's AR forecasting gives you predicted payment dates based on each customer's historical payment behaviour — accurate inputs for a reliable cash forecast.