13-Week Cash Flow Forecast: Simple Setup Guide

Cash is the main limit on growth. A clear 13-week forecast shows when cash comes in, when it goes out, and how much room you have to act. It fits on one page and updates fast. It guides hiring, ads, and vendor talks. This guide walks through setup, data, and a weekly routine that keeps your view fresh.

Why a 13-week forecast matters

Thirteen weeks is one quarter. It is long enough to plan moves, but short enough to be accurate. Leaders can see gaps early and choose from real options. Teams align on the same numbers each week. Bank partners trust a plan that updates on a set day and ties to the ledger and the bank.

What a 13-week model includes

The model groups cash by source and use. It works best when it is simple.

Core sections

• Beginning cash by bank account
• Inflows such as customer receipts, new bookings that fund prepayments, tax refunds, interest, and other income
• Outflows such as payroll, benefits, contractors, vendors, rent, cloud, tools, taxes, and debt service
• Net change and ending cash each week
• Covenant or target lines if you track a minimum balance

Keep line items short. Most teams use 20 to 40 rows. Use notes for detail when needed, not more rows.

Step 1: Map cash inflows

List every source of cash you expect in the next 13 weeks.

Customer receipts

• Open invoices by due date
• Historic days sales outstanding and real payment habits
• Large customer exceptions that pay on set days only

New sales that drive cash

• Prepaid deals
• Upfront onboarding fees
• Deposits for large orders

Other inflows

• VAT or GST refunds
• Grant draws or subsidies
• Interest on deposits
• Planned equity or debt draws

Use past weeks to set a base. Then adjust for known events, such as launch dates, quarter ends, or contract clauses. Record the method in a short note so a new owner can follow it next month.

Step 2: Map cash outflows

Group spend by type and timing. Start with the largest and most predictable items.

People

• Payroll dates and amounts
• Benefits, commissions, and bonuses
• Contractor payouts and retainers

Vendors and services

• Cloud and software with billing dates
• Manufacturing and logistics
• Agencies, auditors, and legal fees
• Rent and utilities

Taxes and debt

• Sales tax, VAT or GST, and payroll filings
• Estimated income tax
• Interest and principal on loans
• Credit card payments and limits

Other

• Equipment or capex
• Insurance premiums
• Customs and duties

For each line, write the due date rule. Some hit on the 1st or the 15th. Others are net 30 from invoice date. Mark these rules in one place so the next update is simple.

Step 3: Build the weekly calendar and structure

Use a simple layout with one column per week and one row per line item. Start each week on the same day. Many teams use Monday to Sunday.

Structure tips

• Keep one tab for inputs and one for the weekly view
• Lock formulas for net change and ending cash
• Add a small section for new items so updates never break the layout
• Use clear names for lines and keep them stable over time

Include a thin buffer line for unknowns. This helps reflect small shifts in timing without a full edit each day.

Step 4: Link banks and reconcile

Your forecast must tie to real balances. Pull bank feeds into a simple sheet or data tool. Reconcile the ending balance from last week to the bank on a set day. List open items such as deposits in transit or checks not cleared.

Weekly tie-out

• Prior week ending cash equals bank balance after recon
• Any difference is explained in a short note
• Clearing items move off the list the next week

If you run multiple entities, add a small table that shows cash by entity and the total. This helps with rules on who can fund whom.

Step 5: Add scenarios and guardrails

Plans change. Your forecast should show a base case and a downside case at minimum. The difference often sits in the inflow lines and one or two outflows.

Scenarios

• Base: expected receipts based on current pipeline and normal timing
• Downside: slower receipts, one large pushout, or a delayed order
• Upside (optional): early payments or a prepay from a new deal

Guardrails

• A minimum cash target
• A hiring gate tied to a bookings or margin goal
• A vendor payment rule such as “pay on due date unless early pay gains a clear discount”

Show the impact of each case on ending cash, not just on revenue or costs. Decisions are easier when you see cash runway change by week.

Step 6: Run a steady weekly cadence

Pick a day for updates and stick to it. Many teams run the forecast on Monday morning so leaders start the week with a clear view.

Weekly routine

• Pull bank balances and reconcile last week
• Update cash receipts for the prior week
• Update outflows for invoices received and for known spend
• Roll the forecast forward by one week
• Review changes larger than a set threshold
• Share a one page pack with the chart and the key notes

Keep the meeting to 15 minutes. Focus on changes and actions, not every line.

Step 7: Turn the view into actions

A forecast is useful when it drives decisions. Use the view to set simple moves.

Collections

• Call accounts that are late by a set number of days
• Offer small discounts for early payment if cash is tight
• Send clean invoices with correct tax and PO data to avoid pushes

Spend

• Delay non critical tools or projects by a week if needed
• Move large vendor bills to a payment plan with clear dates
• Use purchase orders for items over a set amount

Funding

• If a gap shows, plan draws or bridge options early
• Keep lender updates steady with your one page pack
• Avoid last day requests that strain trust

Record each action in a short log with owner and date. Next week, close the loop.

Common pitfalls and simple fixes

Too many rows
If the sheet has hundreds of rows, updates stall. Fix by grouping small vendors into one line by type. Keep a notes field for detail.

No link to bank
If balances do not tie, trust falls. Fix by adding a weekly recon line and a clearing list.

Timing error loops
If large items land in the wrong week, the view swings. Fix by writing due date rules next to the line and using them every time.

One person knows the model
If only one owner can update, risk is high. Fix by writing a runbook and doing a handoff once a month.

No actions from the view
If meetings are just reviews, nothing changes. Fix by listing three actions each week and tracking them.

Templates, data sources, and owner roles

Templates

• One page layout with inflows, outflows, net change, and ending cash
• A chart that shows ending cash for base and downside cases
• A notes box for key changes and actions

Data sources

• AR aging and invoice due dates
• AP aging and vendor terms
• Payroll schedules and headcount plan
• Tax calendars and loan schedules
• Bank feeds and statements

Owner roles

• Finance owner: maintains the sheet, runs the recon, and sends the pack
• AR owner: updates collections and disputes
• AP owner: updates vendor timing and large bills
• Budget owners: flag large changes or delays

Next steps for your team

Set up the structure this week. Map inflows and outflows. Link banks and reconcile last week’s ending cash. Build base and downside cases. Pick a weekly meeting time and keep it short. In two weeks, you will see trends. In four weeks, you will have a habit that guides clear decisions and reduces stress at month end.

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