What it means
A schedule can look feasible when tasks are timed only by their dependencies, yet two activities may both require the same specialist on Tuesday; if only one specialist exists, the plan has a resource conflict. Levelling moves one or more activities to match capacity, so a task with flexibility might start later or the team may choose a new execution sequence.
The result is a schedule that can actually be staffed. The Project Management Institute discusses levelling after critical-path analysis, weighing activity priority, resource availability and the trade-off between duration and limited capacity.
A simple fictional example has two one-day tasks planned for Monday, each needing the same crane, and scheduling one for Tuesday removes the conflict but may delay a dependent task. Start with valid task logic and duration estimates, and do not hide the crane conflict by pretending an activity takes two days when the work itself takes one.
Float is the time an activity can move without delaying a defined milestone or finish under the current network, so activities with more float are often candidates to move. Levelling does not necessarily delay the final deadline, because if enough float exists conflicts may be resolved within it, but a fixed resource limit can force a later finish when flexibility runs out.
The critical path can change after levelling, and moving a noncritical task may consume float and make it critical, so recalculate dependencies and report the changes. A manager then has choices: add capacity, change scope, revise sequence or accept more time, each with cost and risk, and the software should not silently choose a business trade-off.
The capacity profile matters, since a worker's availability is not a simple name on a calendar if other projects or leave consume time, and resource availability should stay visible as its own constraint. Skills are not interchangeable either, because adding three people who cannot operate a specialist machine does not solve that machine's bottleneck, so model resource types at a useful level of detail.
Levelling can also reduce over-allocation across several projects, as a shared designer may have conflicting deadlines from different managers and a portfolio view can reveal the clash that individual project files miss. Resource smoothing has a narrower goal: even out peaks using available float while leaving the required finish intact.
If no float exists, it cannot remove every peak without changing capacity or the deadline, so do not present it as a complete substitute for levelling. Some tools apply automatic priority rules, and a priority code or smallest-float rule can produce a mathematically valid but impractical schedule, so review supplier dates, handoffs and actual working calendars.
A task may be interrupted or kept continuous depending on work type, since stopping a concrete pour halfway is different from pausing document review, and the revised plan needs owner agreement because a delayed inspection can affect a customer commitment even if the project end stays fixed. When updating after real progress, rerun the capacity view and report original and levelled start and finish dates, conflicts resolved and any deadline change, so that the trade-off is visible; a strong plan does not ask one person to be in two places at once.
In practice
Real-world examples.
Example
A project moves one of two simultaneous crane jobs because only one crane is available. The planner checks that the later job does not sit on the critical path before accepting the move. The updated plan shows the new start date and the dependent task that moves with it.
Example
A shared designer is allocated across two projects after their managers compare milestones. The portfolio view shows that both projects had asked for the same week. One project agrees to start its design review three days later, and both teams record the change.
Example
A team accepts a later finish rather than assigning more work than its specialists can handle. The manager shows the sponsor the original and levelled dates and the cost of temporary help. The sponsor chooses the later finish because it avoids extra spending.
Formula
Calculation
There is no single formula. Compare required resource units by time period with available units, then reschedule activities subject to dependencies, priorities and the chosen deadline constraints. Overload in a period = required units - available units, whenever the result is positive.
Worked example. A fictional project has one crane, available at $1,500 per day if hired in. On Monday, two one-day tasks each need the crane, so required units = 2, available units = 1 and overload = 2 - 1 = 1 crane-day. Moving one task to Tuesday leaves Monday at 1 required against 1 available, and Tuesday at 1 against 1, so the overload is removed.
If a dependent task then finishes a day later and each day of delay costs the project $2,000 in site overheads, the manager compares $2,000 of delay with the $1,500 cost of hiring a second crane for Monday. On cost alone, hiring wins by $500, but the manager would also check access, safety and whether the later finish affects a customer milestone.Case study
Seen in the real world.
In this entirely fictional case, Atlas Build plans two one-day inspections requiring one specialist on Monday. Levelling moves one to Tuesday and shows a dependent milestone moving too. The manager compares the later finish with the cost of temporary help before agreeing to a revised schedule. The software output is a proposal, not an automatic commitment.
Watch out
Common mistakes.
- Hiding a resource shortage by changing task durations without explanation.
- Assuming levelling can never delay the project finish.
- Letting automatic priorities move customer milestones without review.
Questions
People also ask.
Does levelling always extend the project?
No. Available float may absorb changes, but a hard capacity limit can extend it.
How is it different from smoothing?
Smoothing uses float to keep the finish fixed; levelling may move the finish to honour resource limits.
What should be reviewed afterward?
Check new dates, critical path, milestones, workload and the cost of alternatives.
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