Project Backlog vs Available Delivery Capacity

A project backlog is work already accepted but not yet completed. It can be measured in contract dollars, remaining hours, or deliverables, and those measures answer different questions. Capacity is the work the team can actually complete in a particular period. A large dollar backlog does not establish that the next delivery date is achievable, especially when the remaining work requires one scarce skill.

Convert accepted work into remaining hours

Assume three hypothetical projects require 60, 90, and 50 delivery hours. The backlog is 200 hours. The team has 50 productive delivery hours available each week after planned absence, administration, and existing support obligations. Dividing 200 by 50 gives four weeks of aggregate work. This is a workload indicator, not a promise that every project can be finished in four weeks.

Project A alone needs 60 hours in week one, exceeding the team's 50-hour capacity by 10 hours. If the specialist has only 15 available hours that week, A also has a 10-hour specialist gap. These gaps overlap: the specialist work is part of the 60 hours, so adding both gaps as if they were independent would overstate the shortage.

Schedule dependencies before adding another project

Place tasks in the weeks when inputs, approvals, and specialist time are available. Work that cannot begin until the client supplies files should not consume fictitious productive capacity beforehand. It may still occupy a reserved time slot, which is a different planning constraint. Record whether that reservation can realistically be released to another client at short notice.

Now consider a proposed 40-hour job due in week two. The four-week total would rise to 240 hours against 200 hours of capacity. The additional 40 hours cannot be accepted under an unchanged schedule merely because some existing invoices will be collected later. Cash collection and delivery capacity are separate constraints. A feasible alternative needs a changed deadline, reduced scope, or explicitly costed additional capacity.

Reconcile the backlog every week

Opening remaining hours plus accepted additions, minus completed hours, plus revised estimates should equal closing remaining hours. If 50 hours are completed but a discovery adds 20 hours of work, the 200-hour backlog becomes 170 hours, not 150. The extra estimate is not a second sale; it changes the effort needed to deliver the commitments already made.

Keep unaccepted proposals outside confirmed backlog and show them as separate demand scenarios. Zero available capacity makes weeks of coverage undefined; it does not clear the backlog. Whole-job sequencing, differing skills, and uncertain remaining effort limit the average ratio. Use it to identify where a dated schedule needs attention, with profitability and cash forecasts reviewed alongside it.

Method references: OpenStax: Prepare Operating Budgets. Accessed October 22, 2026. All dollar figures are hypothetical worked examples.