Contractor Project Cash Flow + Retention Calculator

The industry-standard payment workflow puts the contractor in the financing role. The contractor performs work in month N, bills at end of month N on AIA G702 / G703 or equivalent, the owner has time to review and approve the billing (often 7-14 days), then pays minus retention within the contract terms (net 30 in most private commercial work, longer in some public works and distressed environments). During those 30-60 days the contractor pays labor weekly, materials net 30, and subs net 30-45. The mismatch is structural — the contractor is funding the project from its working capital until owner payment catches up. The OWNER could pay in advance (deposit-based work, common in residential remodel under $10K) but commercial and large residential contracts use the progress-payment model because it ties owner payment to verifiable work-in-place and limits the owner's exposure if the contractor underperforms. The trade-off is real: in exchange for the financing risk, the contractor controls the work sequence and bills on its own progress schedule, but the working-capital requirement is the cost of that control. CFMA-benchmarked construction working-capital ratios (current assets / current liabilities) run 1.3-1.8 across most segments, with peak working-capital deployment routinely 20-30% of contract value mid-project.

Retention (also called retainage) is a percentage of each progress billing withheld by the owner as security that the contractor will complete the project and address punch-list deficiencies. Typical 5-10% of each draw. The economic theory: at substantial completion the contractor has incentive to walk away and avoid the unprofitable punch-list cleanup; retention is the financial leverage that ensures the contractor returns to finish the small items (paint touch-up, door alignment, fixture re-aim, missing keys). The withheld retention is released in stages — typically 50% at substantial completion (the project is occupiable) and 50% after punch-list completion and lien-waiver delivery. State statutes cap retention in many jurisdictions: California Civil Code §8812 limits private-work retention to 5%; Texas Property Code Chapter 53 governs retainage on private and public work; similar statutes exist across most states. Public works retention is statutorily capped in most jurisdictions (Federal Acquisition Regulation, state procurement codes). Retention is a contract-level concept; the GC typically withholds the same percentage from subcontractor billings (cascading retention down the contract chain) which means the sub also finances the project at the GC's direction.

Substantial completion is defined in AIA A201 §9.8.1 as "the stage in the progress of the Work when the Work or designated portion thereof is sufficiently complete in accordance with the Contract Documents so that the Owner can occupy or utilize the Work for its intended use." The architect issues a Certificate of Substantial Completion (AIA G704) listing the punch-list items remaining. Substantial completion matters for three reasons. First, the first tranche of retention (typically 50%) is released at substantial completion. Second, the warranty period typically starts at substantial completion. Third, the risk of loss and the responsibility for utilities and insurance typically shift to the owner at substantial completion. Disputes over substantial completion are common in punch-list-heavy projects where the owner asserts that lingering deficiencies mean the project is not substantially complete; the contractor asserts that the deficiencies are minor and the project is occupiable. The G704 process is the standard dispute-resolution starting point.

PAY-WHEN-PAID is a timing provision: the GC pays the sub WHEN the GC receives payment from the owner, but the GC remains obligated to pay the sub even if the owner never pays (the owner default is the GC's risk). Pay-when-paid is enforceable in virtually all jurisdictions and is the default contract provision in most GC-sub agreements. PAY-IF-PAID is a conditional provision: the GC pays the sub ONLY IF the GC receives payment from the owner, and the owner default shifts the loss to the sub. Pay-if-paid is more onerous and is unenforceable as an unenforceable condition precedent in many jurisdictions (California, New York, Maryland, Wisconsin, and others have rejected it under common law or statute); some states enforce it only if the language is conspicuous and unambiguous. The distinction is critical to cash-flow planning: under pay-when-paid, the sub can be confident the GC will pay (eventually), so the sub finances at the GC's payment pace. Under pay-if-paid in an enforcing state, the sub is at full risk of the owner's default, which the sub may price into its bid as a risk premium. Verify the controlling state law and the specific contract language with construction counsel.

Surety bond underwriting evaluates a contractor's bonding capacity (the total contract value the contractor can carry at one time) based primarily on net worth and working capital. The standard surety underwriting heuristic is total work-on-hand capacity equals roughly 10-20x working capital and roughly 20x net worth. A contractor with $200K working capital might have a single-job capacity of $2M-$4M and an aggregate capacity of $4M-$10M. The cash-flow projection from this calculator interacts with bonding capacity in two ways. First, the peak working-capital requirement on a single project must be available — if a $1M project requires $250K peak working capital, the contractor needs that capital available without consuming the working-capital base that supports bonding capacity for other in-progress and pending work. Second, the bond underwriter will review the cash-flow projection and the working-capital deployment across the contractor's full work-on-hand portfolio before issuing the bond. A contractor that consumes its working capital on one large project loses bonding capacity for additional work until the first project's working capital frees up. This is why GCs with large in-progress projects often slow their bidding pace — not because they lack opportunities, but because they lack bonding capacity to take additional work.

Step-down retention reduces the retention percentage at a milestone (typically 50% project completion) — for example, withholding 10% on draws through 50% completion, then reducing to 5% thereafter and releasing the excess withheld in the next draw. Some contracts allow step-down retention to recognize that the contractor has demonstrated performance and the security need is lower in the back half of the project. Public-works contracts in some states (California, Massachusetts, others) authorize step-down by statute. The AIA A201 standard form does not include step-down; it must be negotiated as a contract modification. The calculator does NOT model step-down retention — it assumes a constant retention percentage across all draws. For projects with negotiated step-down provisions, the actual working-capital requirement is lower than the calculator projects (less cash held in retention during the back half) and the cash-flow profile is more favorable. Adjust the projection manually if step-down applies.

The calculator distributes billing evenly across the project duration, which is the simplest defensible assumption and matches a typical schedule-of-values that approximates time-and-trade-balanced progress. Real projects often have front-loaded mobilization (the contractor bills mobilization, site setup, and demolition in months 1-2 at a disproportionate share of contract value) or back-loaded finish work (the high-value finishes — millwork, cabinetry, fixtures, technology — bill heavily in the last two months). Front-loading reduces the peak working-capital requirement because the contractor recoups cash early; back-loading increases it because the contractor finances the bulk of the work before any payment catches up. The calculator does NOT model uneven distribution. For more-precise cash-flow planning on a specific project, build the schedule of values explicitly on AIA G703 and run a separate billing-curve model. The Fennec Press contractor-operations bundle includes a schedule-of-values workbook with built-in cash-flow projection.

If the owner disputes a billing, the contractor's first step is to verify the dispute against the AIA G702 / G703 line items and address the specific items the owner has challenged. Common dispute sources: alleged non-conforming work, alleged over-billing relative to actual completion, missing lien waivers from subs, schedule-of-values disagreement. The contractor should issue a written response within the contract notice period (typically 7-14 days) and request that the disputed amount be paid less the disputed portion. If the owner refuses to pay any portion or extends delay beyond the contract payment terms, the contractor has three escalation pathways. First, MECHANIC'S LIEN — file a mechanic's lien against the property within the state-specific lien-filing window (typically 60-120 days from last work performed). The lien creates a secured claim that survives transfer of the property and forces the owner to address payment to clear title. Second, STOP NOTICE or STOP-WORK on public works — many states allow stop-notice procedures on public works that capture funds at the public agency level. Third, BREACH OF CONTRACT litigation or arbitration under the contract dispute-resolution clause. State prompt-pay statutes also entitle the contractor to interest on late payments (typically 1-1.5% per month) and sometimes attorney fees. The combination of lien rights, prompt-pay interest, and dispute-resolution provisions gives the contractor meaningful leverage but the operational reality is that disputed billings extend the working-capital requirement and the contractor must have the line-of-credit capacity to absorb the delay.

The calculator is a working-capital planning tool, not a full cash-management system. It does NOT model uneven billing distribution (front-loaded mobilization, back-loaded finish work, schedule-of-values cash-loading strategies). It does NOT model step-down retention. It does NOT model owner payment delays beyond the input net-payment-term assumption. It does NOT model subcontractor pay-when-paid versus pay-if-paid cash-flow timing differences. It does NOT compute interest on owner-financed lines of credit consumed by the working-capital requirement. It does NOT model multi-project portfolio cash-flow aggregation (the bonded contractor with three concurrent projects has aggregate working-capital deployment that exceeds any single-project calculation). It does NOT model the surety-bond capacity consumption explicitly — see the contractor License Bond Cost Calculator for bond pricing, and consult a surety underwriter for capacity sizing. It does NOT model change-order cash-flow impact — see the Change Order Pricing Calculator. For comprehensive project financial planning, the peak working-capital requirement this calculator produces is one input to a full pre-bid analysis that includes bonding capacity, line-of-credit availability, and portfolio-level working-capital deployment.