Cash Flow Gap Calculator

What Is the Cash Flow Gap?

The cash flow gap is the difference between when you pay your costs and when you collect your revenue on a construction job. On most projects, money goes out before it comes in — you pay your workers every week, your material suppliers within 30 days, and your subcontractors when you get paid, but your owner or GC may take 45 to 60 days to process your pay application and cut a check. That timing difference has to be funded from somewhere.

For contractors, the cash flow gap is one of the most persistent financial challenges in the business. A company can be profitable on paper and still run out of cash mid-project if the gap is larger than the company's working capital can absorb.

Why the Gap Is Larger Than Most Contractors Expect

Most contractors have a rough sense of their collection lag — they know it takes about 45 days to get paid after submitting a pay app. What they often underestimate is the compounding effect of retainage.

On a $2 million job with 10% retainage and a 45-day collection lag, you will collect only 90 cents of every dollar you bill during the job. The remaining 10% — potentially $200,000 — sits with the owner for the entire job duration plus whatever close-out period follows. During that time, you are still paying 100 cents of every dollar of cost. The gap between what you have paid out and what you have collected grows throughout the job and only begins to close when retainage is released.

What This Calculator Models

This calculator estimates the cash flow gap for a single job based on your specific contract parameters. It models the following:

Billings are submitted monthly in equal amounts over the job duration and collected after your specified lag. Owner retainage is withheld from each billing at the rate you specify and released as a lump sum after job close-out.

Labor is paid in the month the work is performed. Materials are paid one month after delivery. Subcontractors are paid when you are paid — Pay-When-Paid — net of sub retainage withheld at the same rate as owner retainage. Sub retainage is released at the same time as owner retainage. Other costs are paid in the month incurred.

The calculator tracks the cumulative cash position month by month and identifies the peak cash gap — the maximum amount of working capital you will need to fund the job at any single point.

How to Use the Results

The peak cash gap tells you the maximum line of credit draw or working capital reserve you need to have available for this job. If your peak cash gap is $380,000 and your line of credit is $250,000, you have a problem that needs to be solved before the job starts — not after.

The retainage balance tells you how much of your earned revenue is locked up and unavailable during the job. On larger jobs, this can be a significant number that strains cash flow even when the job is going well.

The monthly detail table shows exactly when money comes in and when it goes out, so you can identify the specific months where the gap is widest and plan accordingly.

Managing the Cash Flow Gap

Front-load your schedule of values. The schedule of values determines how much you bill in each month relative to the work completed. Experienced contractors front-load their SOV — allocating more value to early work items — to accelerate early billings and reduce the peak gap.

Negotiate better retainage terms. Retainage is negotiable on many projects, particularly for subcontractors with a strong track record. Reducing retainage from 10% to 5% on a $2 million job frees up $100,000 in cash flow.

Submit pay applications on time every month. Every day you delay submitting a pay app is a day added to your collection lag. Contractors who submit on the last possible day of the billing window consistently have worse cash flow than those who submit on the first.

Know your gap before you bid. The cash flow gap is a cost of doing business. If funding it requires drawing on a line of credit at 8% interest, that interest cost belongs in your overhead rate — not absorbed silently as a drag on your margin.