Personal cash flow forecast: see your future balance

Expense trackers describe the past. They tell you that you spent a certain amount on groceries last month, grouped into categories. That is useful for noticing habits, but it never tells you whether next Tuesday's direct debit will clear.

• Tracking looks backward; forecasting looks forward.
• Tracking groups money by category; forecasting orders it by date.
• Tracking tells you what happened; forecasting tells you what will happen if nothing changes.

A forecast points the other way. Every planned payment is placed on the exact date it happens, and the balance is recalculated day by day from today onward.

A budget is a monthly limit: how much you intend to spend on each category. It assumes money arrives and leaves smoothly across the month, which it rarely does.

A forecast has no categories and no limits. It only cares about amounts and dates. You can be perfectly within budget for the month and still be short on the 12th, because rent leaves the account before the salary arrives. A budget cannot see that; a forecast can.

The output is simply your balance over time — per account and in total.

• The balance on every future day, not just at month end.
• Every recurring payment: salary, rent, loan instalments, subscriptions.
• One-off items you already know about, such as a flight or an insurance renewal.
• Several accounts at once, so you can see which one runs dry first.
• The first date a balance drops below zero, if it ever does.

Income and expenses almost never line up neatly. Salary lands once a month; rent, childcare and card payments land on their own dates. Someone whose income comfortably exceeds their outgoings can still be short for four days in the middle of the month.

That gap is a timing problem, not an overspending problem, and the fix is usually a timing fix: move a payment, delay a purchase by a week, or transfer money between accounts before the shortfall date.

Because a forecast places every known payment on a date, a shortfall shows up long before it happens — with a date attached. That turns a vague worry into something you can act on, while there is still time to act.

Cash Flow Planner does exactly this: you enter your accounts and current balances, add income and expenses (once or recurring), and the forecast recalculates as you type. You can try it without signing in.