Skip to main content
Utilisation measures how much of your available time is spent on billable work. It’s a key efficiency metric that shows whether you’re making good use of capacity.

​
The Formula

Utilisation is a simple ratio expressed as a percentage:
The Formula
Utilisation % = (Billable Minutes ÷ Available Minutes) × 100
  • Billable Minutes: Time logged to client work that will be charged
  • Available Minutes: Working time available after leave and holidays

​
What Counts as Billable?

Time is considered billable when it’s logged to:

Client Tasks

Work on client tasks and subtasks marked as billable

Help Desk Tickets

Client support and troubleshooting

Scheduled Work

Any client-facing work that will be charged

Billable Projects

Project work tied to client contracts
Only time entries with isBillable = true count toward utilisation. Non-billable time (meetings, admin, internal projects) is tracked but doesn’t count toward this metric.

​
What Counts as Available?

Available time is your productive capacity—the time you have available for work:
Available Time
Available Minutes = (Working Days - Leave Days) × Daily Capacity

​
Working Days

A working day is any weekday (Monday-Friday) that is not:
  • A weekend (Saturday/Sunday)
  • A UK bank holiday
  • A day you’re on approved leave

​
Daily Capacity

Your daily capacity is the productive minutes available per day:
TypeMinutesHoursPurpose
Default Capacity390 minutes6.5 hoursSchedule allocation, utilisation
Billing Day450 minutes7.5 hoursDay rate calculations only
Why 6.5 hours and not 7.5?The 6.5-hour default is realistic productive time. It accounts for:
  • Meetings and standups
  • Context switching
  • Email and admin work
  • Breaks and downtime
The 7.5-hour “billing day” is used for day rate calculations but isn’t realistic for daily capacity planning.

​
Role-Based Capacity

Different roles may have different daily capacities:
RoleTypical CapacityReason
Developer6.5 hoursStandard productive time
Designer6.5 hoursStandard productive time
PM/CSM5 hoursMore meetings and coordination
Leadership4 hoursStrategic work, meetings
These can be configured per person or per role in the system.

​
Worked Example: Individual Utilisation

Scenario: Sarah’s February performance
StepCalculationResult
1. Calculate Working Days
Days in February28 days
Weekends (Sat/Sun)8 days
Working days28 - 820 days
UK bank holidays in Feb0 days
Net working days20 - 020 days
2. Subtract Leave
Leave taken2 days
Net available days20 - 218 days
3. Calculate Available Time
Daily capacity390 mins (6.5h)
Available minutes18 × 3907,020 mins
Available hours7,020 ÷ 60117 hours
4. Get Billable Time
Billable minutes logged5,265 mins
Billable hours5,265 ÷ 6087.75 hours
5. Calculate Utilisation
Utilisation %5,265 ÷ 7,020 × 10075% ✅
Sarah hit the target utilisation of 75%!

​
Target: 75%

The goal is 75% utilisation, not 100%. Here’s why:
Aiming for 100% utilisation means:
  • ❌ No time for training and development
  • ❌ No buffer for urgent work or emergencies
  • ❌ High risk of burnout
  • ❌ No time for internal improvements
  • ❌ No flexibility for planning and thinking
100% utilisation is unsustainable and unhealthy.
The remaining 25% of time is for valuable non-billable work:
  • ✅ Internal projects - Tools, processes, documentation
  • ✅ Training - Learning new skills and technologies
  • ✅ Meetings - Standups, planning, reviews
  • ✅ Admin - Timesheets, expenses, communication
  • ✅ Innovation - Exploring new approaches
  • ✅ Business development - Proposals, pitches
This work has real value even though it’s not directly billable.
Not everyone should target 75%:
RoleTargetWhy
ICs (devs, designers)75%Most time can be billable
PMs/CSMs60-70%More meetings and coordination
Managers50-60%Team support, 1-on-1s, planning
Leadership40-50%Strategic work, business development

​
Utilisation Levels

CharleOS uses bands to categorize utilisation:
LevelRangeBadgeWhat It Means
Over-utilisedGreater than 90%● RedBurnout risk, no buffer for urgent work
On Track80-90%● GreenSlightly above target, still healthy
Target70-80%● GreenIdeal range, good balance
Below Target50-69%● AmberBelow target but normal for some periods
LowLess than 50%● RedUnder-utilised, may indicate issues
What it means:
  • Very little buffer for non-billable work
  • High risk of burnout
  • No time for improvement or learning
Common causes:
  • Tight deadlines across multiple projects
  • Under-staffing
  • Over-commitment
Actions:
  • Consider hiring or redistributing work
  • Review and adjust schedules
  • Ensure proper time off is taken

​
Department & Agency Utilisation

Utilisation can be aggregated across teams and the entire agency:

​
Department Utilisation

Department Formula
Dept Utilisation = (Total Billable Minutes ÷ Total Available Minutes) × 100
Worked Example - Design Department in February:
Team MemberAvailable MinsBillable MinsIndividual %
Sarah7,0205,26575%
Mike7,0204,91470%
Emma5,8504,68080%
Department Total19,89014,85974.7% ✅
The department as a whole is just under the 75% target.

​
Agency Utilisation

Same calculation across all billable staff in the agency:
Agency Formula
Agency Utilisation = (All Billable Minutes ÷ All Available Minutes) × 100
Only staff with hasBillableCapacity = true are included in agency utilisation. This excludes admin, leadership, and other non-billable roles.

​
Where to See Utilisation

Utilisation metrics appear throughout CharleOS:
See your personal utilisation for:
  • Last 7 days
  • Last 30 days
  • Current month
  • Custom date ranges
Includes a comparison to the previous period.
See utilisation for:
  • Each team member
  • Your department as a whole
  • Trends over time
Helps identify who has capacity and who might be over-loaded.
Admin users see agency-wide utilisation:
  • Current utilisation percentage
  • Month-over-month trends
  • Department comparisons
Helps with high-level capacity planning.
Utilisation is shown alongside capacity in:
  • PM capacity views
  • Schedule planning
  • Resource allocation tools

​
What Affects Utilisation

Understanding what drives utilisation helps you improve it:

​
Things That Lower Utilisation

FactorImpactHow to Address
Annual LeaveReduces available timePlan around leave, ensure coverage
Internal ProjectsTime not billed to clientsBalance internal vs client work
Between-Project GapsNo billable work availableImprove pipeline, schedule better
Meetings & AdminNecessary but not billableKeep efficient, consider whether all are needed
TrainingInvestment in skillsImportant for long-term, schedule strategically
Client BlockersWaiting for feedback/approvalsFollow up proactively, have backup work

​
Things That Raise Utilisation

FactorImpactConsideration
Full Client PipelineMore billable work availableEnsure quality doesn’t suffer
Efficient ProcessesLess time on non-billableGood, but don’t eliminate necessary work
Good SchedulingMinimal gaps between tasksBalance with realistic timelines
Reduced Internal WorkMore time for clientsDon’t neglect process improvements
Don’t optimise for utilisation alone!High utilisation at the expense of:
  • Team wellbeing
  • Quality of work
  • Process improvements
  • Learning and development
…is counterproductive. Aim for sustainable high utilisation, not maximum utilisation.

​
Common Misconceptions

Reality: 75% is the target for healthy, sustainable productivity.100% utilisation means:
  • No time for growth
  • No buffer for problems
  • High burnout risk
  • Declining quality over time
Reality: The 25% non-billable time drives long-term value.Internal work includes:
  • Process improvements that save time later
  • Tool development that increases efficiency
  • Training that improves skills
  • Planning that prevents problems
These investments pay dividends.
Reality: Low utilisation can have many legitimate causes:
  • New starters ramping up
  • Between projects (pipeline issue, not individual)
  • Waiting on client approvals (blocker, not laziness)
  • Seasonal quiet periods
  • Heavy internal project work
  • Training and development
Always investigate the cause before jumping to conclusions.

​
How It’s Calculated in the System

CharleOS calculates utilisation at multiple levels:
1

Individual Calculation

For each user with hasBillableCapacity = true:
  1. Get daily capacity (role-based or default 390 mins)
  2. Calculate working days (exclude weekends and bank holidays)
  3. Subtract approved leave (including half-days)
  4. Multiply by daily capacity = available minutes
  5. Sum billable time entries where isBillable = true
  6. Calculate: utilizationPercent = (billable / available) × 100
2

Department Aggregation

For each department:
  1. Sum billable minutes for all department members
  2. Sum available minutes for all department members
  3. Calculate: deptUtilization = (totalBillable / totalAvailable) × 100
3

Agency Aggregation

For the entire agency:
  1. Sum billable minutes for all users with hasBillableCapacity = true
  2. Sum available minutes for all billable users
  3. Calculate: agencyUtilization = (allBillable / allAvailable) × 100
4

Daily Snapshots

Every night at 1 AM UTC, utilisation is captured in metricSnapshot table:
  • Stores cumulative month-to-date values
  • Enables historical trend analysis
  • Used for charts and reports

​
Tips for Healthy Utilisation

Leave reduces available time (denominator), which increases utilisation percentage. If someone takes 2 weeks off, their utilisation that month will naturally be higher.
Internal projects are valuable but should be balanced with billable work. If utilisation drops significantly, review internal project priorities.
Good scheduling minimizes gaps between projects and ensures smooth transitions. Poor scheduling creates idle time that lowers utilisation.
Client approvals, feedback delays, and external dependencies can kill utilisation. Follow up proactively and have backup work ready.
Sustainable 75% is better than burnout-inducing 95%. Protect team capacity and mental health.

Capacity

Utilisation measures billable vs available time—capacity defines available time

Day Rates

High utilisation helps day rates, but efficiency matters more for profitability

Efficiency

Utilisation shows how much time is billable, efficiency shows how well that time is used

Time Tracking

Learn how to log time entries that feed into utilisation calculations