← Subcontractor Cash Flow Planner
How much cash do you need for net 30, 45, 60, or 90 payment terms?
Payment terms are the single biggest lever in a subcontract's cash gap, because every extra day of terms is another day your materials and overhead sit unfunded. Here is the arithmetic on a $10,000 subcontract at five common terms, holding everything else — materials, weekly burn, retention, buffer, and starting cash — at the calculator's own defaults.
Cash needed and funding gap at five payment terms
| Payment terms | Expected payment day* | Cash needed before payment | Funding gap |
|---|---|---|---|
| Net 15 | Day 29 | $5,400 | $400 |
| Net 30 | Day 44 | $6,900 | $1,900 |
| Net 45 | Day 59 | $8,400 | $3,400 |
| Net 60 | Day 74 | $9,900 | $4,900 |
| Net 90 | Day 104 | $12,900 | $7,900 |
*Contract terms plus the calculator's 14-day late-payment buffer, which models the gap between "invoice due" and "invoice actually paid" that shows up across the trades even on paper-clean contracts.
Cash needed grows by exactly $700 for every extra 7 days of terms — that is the weekly burn rate doing the work, not the invoice size or retention, both of which are held constant across this table. The funding gap grows just as fast because starting cash ($5,000) does not move: each 15-day step from net 15 to net 90 adds roughly $1,500 to the gap.
The takeaway is not "avoid long terms" — longer terms are often non-negotiable on larger contracts. It is that the same $10,000 subcontract needs very different working capital depending on the terms alone, so the terms line in a contract is worth pricing into your cash plan before you sign, not after materials are already ordered.
Open the calculator and enter your own invoice, materials, burn rate, and terms to see your actual gap. Nothing you enter is uploaded.
This page is arithmetic, not legal, tax, financial, or accounting advice. It does not tell you what terms to accept or predict when a specific client will actually pay.
Common questions
How much cash do I need to carry a subcontract on net 30 payment terms?
It depends on your materials cost and weekly burn rate, not just the invoice size. On this calculator's own defaults — $2,500 in materials, $700 a week in overhead, a 14-day late-payment buffer on top of the 30-day terms — cash needed before payment works out to $6,900. Compared against $5,000 in cash available for the project, that is a $1,900 funding gap you would need to bridge with more starting cash, a materials deposit, progress billing, or a line of credit.
How much does the funding gap grow if payment terms stretch from net 30 to net 60 or net 90?
Roughly linearly with the extra weeks, because the calculator multiplies your weekly burn by the days until expected payment. Going from net 30 to net 60 on the same $10,000 subcontract raises cash needed from $6,900 to $9,900, and the funding gap from $1,900 to $4,900 — a $3,000 increase driven entirely by an extra 15 days (net 60 plus the same 14-day buffer versus net 30 plus that buffer) of overhead that has to be funded before the invoice pays. Net 90 terms nearly double cash needed again, to $12,900, for a $7,900 gap.