13-Week Cash Forecast for Project-Based Firms

At a glance: A 13-week view shows when cash pinches hit. Forecast three things weekly: starting cash, expected inflows, and outflows. Keep it simple, but structured enough to update in minutes.

Jump to: Copy the 13-week table

Why 13 weeks works for services

Thirteen weeks is long enough to see payroll cycles, project milestones, tax payments, and seasonal patterns—but short enough to manage actively. Update it once a week; meet for 15 minutes to decide collections priorities, spending deferrals, or scheduling changes.

What goes where

Inflows are cash you reasonably expect to hit the bank during the 3 month period:

• Retainers (new work or replenishments)
• Milestones (progress billing tied to deliverables)
• Collections (A/R you expect to land over the next 1-4 weeks)
• Client Deposits (payments made on proposals and other non time billing deposits on account)
• Other Inflows (refunds, credits, interest)

Outflows are payments leaving the bank during the 3 month period. Include your normal items and be explicit about scheduled auto-payments:

• Payroll (gross plus employer taxes/benefits if paid from operating cash)
• Rent & fixed overhead
• Subscriptions / software
• Accounts Payable (vendors, contractors, materials)
• Taxes (income, and sales/use where applicable)
• Credit card payments (principal + fees if applicable)
• AutoPay / ACH drafts on a regular cadence:
  • Professional services on retainer
  • Payroll provider fees
  • Loan payments
  • Sales tax payments

Tip: On the template, don’t lump everything into a single “Inflows” or “Outflows” column. Add simple category columns (e.g., Retainers, Milestones, Collections, Payroll, AP, Taxes, CC Payments). It’s much easier to update future weeks and scan patterns at a glance.

Weekly review rhythm (15 minutes)

1. Reality check: Did last week’s expected inflows actually arrive? If not, move them forward and flag for collections.
2. Pinch points: Any week where End Cash dips below your floor? Plan deferrals, accelerate collections, or shift start dates.
3. Decisions: Who calls which customer? What AP gets deferred? What spend pauses for a week?

FAQs

Should I forecast by cash or accrual?

Cash. This tool is about bank timing, not GAAP measurement. Use accrual reports for profitability; use this for runway and “can we start that project?” decisions.

How often do I update the 13-week view?

Weekly. Roll the sheet forward each week, replace assumptions with actuals, and adjust future weeks based on signed work and collections probability.

What’s a healthy cash buffer?

Long-term goal: 3 months of operating expenses. Floor: 1 month of operating expenses. If your 13-week view shows End Cash breaching the floor, take action now—bring forward collections, delay discretionary spend, or re-sequence project starts.

How do retainers and milestones help cash?

Retainers shift risk from delivery to kickoff; milestones smooth inflows across the project instead of bunching them at the end. Both reduce drawdowns in your 13-week view.

Disclaimer: This article is for general education and may not reflect your specific facts. Consult your finance or tax professional for advice.