Why 13 weeks

Thirteen weeks is roughly one quarter. It is long enough to see a seasonal turn and short enough to be specific. A 12-month budget is a plan; a 13-week forecast is a survival tool. You need both, but when cash is tight, the weekly view wins.

The columns that matter

  • Week beginning — Monday dates, thirteen rows.
  • Opening cash — the actual bank balance, reconciled.
  • Collections — expected receipts, by customer, with a confidence level.
  • Committed outflows — payroll, rent, taxes, loan payments, critical vendors.
  • Discretionary outflows — the spending you can move or stop.
  • Closing cash — opening + receipts − outflows.
  • Buffer — the minimum cash you refuse to go below.

Build it in one sitting

  1. Export the last 90 days of bank transactions. Group them into the columns above.
  2. List every known receivable and the date you actually expect it — not the invoice due date.
  3. List every committed payment for the next 13 weeks, including quarterly taxes and insurance.
  4. Add a “base,” “slow” and “bad” scenario for collections. Most businesses are too optimistic about timing, not amount.
  5. Mark the first week where closing cash falls below your buffer. That is your decision point.

The MCA problem

Merchant cash advances are repaid through a percentage of daily or weekly receipts. The factor rate looks small, but the effective annualized cost can be very high, and stacked advances can consume a large share of every deposit. If you are taking a new advance to cover the last one, the forecast should show it explicitly: remittances by week, remaining balance, and the true cost of the next dollar.

What to do when the line goes negative

You have four levers: collect faster, pay later, spend less, or bring in cash. In that order. Collecting faster means calling the three customers who owe the most, today. Paying later means negotiating terms with vendors before you miss a payment. Spending less means stopping the discretionary line. Bringing in cash means a loan, an investor or a sale — usually the most expensive option.

Use it in the lender conversation

A lender or creditor will ask: what happened, what have you changed, and how will you repay? The forecast answers the third question. Bring the base case, the downside case and the specific actions that keep the buffer intact. That is a far stronger conversation than a story.

This is general education, not individualized financial or legal advice.