What a Completely Full Week Actually Costs
A hundred per cent chargeable means no slack, and slack is what absorbs variation. What a firm gives up at the top of the range.
A week entirely on client work contains no time to absorb anything unexpected. No slack is not an achievement; it is a decision to have no capacity for variation.
The commercial question in “What a Completely Full Week Actually Costs” needs a clean distinction between time recorded, time approved, time billed and money received. Teams evaluating a practical route to attendance sheet template for attendance sheet template can strengthen the work-record part of that chain while leaving invoice totals, tax and settlement to the appropriate finance system.
Variation arrives regardless, and in a fully committed week it is paid for by something.
The assumptions behind “What a Completely Full Week Actually Costs” can also be tested against European Commission project-management guidance. Record which recommendations apply to the real workflow and which do not.
What slack absorbs
A client needing something urgently. An error found late. A colleague off sick. A piece of work taking longer than scoped.
- A client needing something at short notice.
- An error found late in a piece of work.
- A colleague off sick mid-engagement.
- Work taking longer than the scope assumed.
In a week with slack, these are absorbed. In a full week they displace something or extend the day.
The queueing point
Systems run near full capacity develop queues that grow faster than the load. This is arithmetic rather than management theory and it applies to people's weeks.
At ninety-five per cent committed, a small delay propagates for weeks. At eighty, it absorbs.
What propagation looks like in a firm
A slipped engagement pushes the next, which pushes the next. Clients wait, deadlines move, and the effect persists long after the original cause.
Firms experience this as chronic lateness with no identifiable cause, because the cause was the commitment level.
The optimum is not the maximum
For any system with variable arrival and variable duration, the best-performing commitment level is below a hundred per cent.
How far below depends on how variable the work is. Firms with lumpy, urgent, client-driven work need more slack than firms with predictable pipelines.
What the slack is for, specifically
Absorbing variation, and doing the work the earlier notes describe: training, improvement, supervision, development.
These are the same hours. A firm that commits them all to client work loses both functions at once.
The illusion of the full week
A firm at ninety-five per cent looks maximally efficient on a utilisation report and is in fact operating with no margin, which shows up as lateness, rework and overtime.
Three costs, none of them visible on the report that produced the decision.
What the overtime is really doing
Providing the slack the schedule removed, unpaid and unplanned.
A firm with high utilisation and high overtime has not eliminated slack; it has moved it outside contracted hours, where it is invisible and borne by individuals.
Choosing the level deliberately
Decide what share of capacity is committed to client work and what is held for variation and internal work, and state it.
Eighty per cent committed and twenty held is a plan. Ninety-five per cent committed with no held time is also a plan, usually an unstated one.
The number to publish
Not utilisation against a target but committed capacity against the level the firm chose, with the held time named and accounted for.
That framing makes the trade-off visible and removes the implication that higher is always better.
What this changes in planning
Capacity planning starts from the target commitment level rather than from total available hours.
A firm of fifty people at eighty per cent commitment has forty people's worth of sellable capacity, and planning on fifty guarantees the problems above.
Where high commitment is genuinely right
Short periods, predictable work, a known peak with a known end.
Sustained high commitment is different in kind, and the difference is whether the firm has decided when the slack comes back.
Where the slack goes when it is removed
Into evenings, into reduced quality, into deferred internal work, and into lateness that propagates.
Four places, and the week's recorded utilisation rises in all four cases while the firm's position worsens in three of them.
The fourth, deferred internal work, worsens the position later, which makes it the hardest to connect to the decision that caused it.
The number a firm should decide rather than measure
Committed capacity: the share of available hours the firm intends to sell. It is a plan, not an observation.
Deciding it makes everything else interpretable. A firm that has committed eighty per cent and achieved seventy-eight has a small gap. A firm that has not decided and achieved seventy-eight has no way to know whether that is good.
Most firms have never set this number, which means their utilisation figure is measured against an implicit target of a hundred per cent — a level that, as this note argues, no firm with variable work should want, and none has ever deliberately chosen.
Variability decides the level
A firm with predictable, scheduled work can commit a higher share of capacity than one with urgent, client-driven work, because it has less variation to absorb.
So the right commitment level is a property of the work rather than a target to be maximised, and two firms with the same figure may be one comfortable and one overcommitted.
Naming the variability is how the level gets chosen rather than drifted into.
The sentence worth keeping
A hundred per cent utilisation is a firm with no capacity to respond, no time to improve, and no margin for error, reported as its best possible result.