Project Cash Flow Calculator

Monthly cash flow = inflows (loan draws, owner contributions) − outflows (labor, materials) over project duration.

Inputs

Result

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General calculation reads

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How to use this calculator

  • Estimate monthly project spend (labor, materials, fees).
  • Estimate monthly inflows (loan draws, owner deposits).
  • Set realistic project duration (add 25% to contractor estimate).
  • Enter your liquid cash on hand at start.

About this calculator

Most construction overruns are timing problems, not budget problems. A 6-month build that runs 9 months means 50% more carrying costs (interest, insurance, alternate housing) on the same scope. This calculator catches the moment when monthly outflows outpace inflows — even profitable projects can fail mid-build if the cash buffer runs dry. Carry at least 2 months of outflows as contingency cash beyond your loan draw.

Frequently asked

Why monthly buffer?+
Loan draws lag work by 30-60 days (inspection + bank processing). You float the gap. Without buffer, work stops mid-job.
How big a buffer?+
Minimum 2 months of outflow. For longer or higher-risk projects: 3-4 months.
Can I float on credit cards?+
Cards charge 18-25% — fast way to lose your renovation profit. Use only for true emergencies, pay off immediately at next draw.
What about my mortgage during build?+
You're likely paying current mortgage AND construction loan interest AND alternate housing. Bake all three into outflow.
When does this matter most?+
Owner-builders, ground-up construction, large remodels, or any project with >9 month timeline.

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