Why Resource Availability Is Often Miscalculated

Resource availability looks quite straightforward.

You have a team.
They work 40 hours a week.
You multiply their hours and plan accordingly.

And yet, plans keep changing. Deadlines aren't met, and teams feel overloaded even when the numbers don’t show it.

This usually isn’t because your team is bad at planning. It’s because resource availability is almost always misunderstood.

Here’s why:

Most plans start with hours.

• - “Tom is available 40 hours”
• - “This task takes 10 hours”
• - “Anna is available 15 hours”

But availability isn’t just time on a calendar.
Think about a typical week:

• - Meetings
• - Emails, messages, status updates
• - Helping others
• - Context switching
• - Small unplanned work

None of this is usually counted as “work,” yet it consumes your team’s capacity every single day.

If someone is booked for 40 hours, their real productive availability might be around 25–30 hours. Or sometimes even less.

When plans don’t consider all these aspects, they will most likely fail.

Another common mistake is assuming every hour is the same.

Work has energy levels and focus requirements that are often ignored.

• - Deep work needs uninterrupted time
• - Creative work doesn’t come between meetings
• - Complex tasks slow down when they are split across many days etc.

Two people may both have “8 hours available,” but those hours can look very different.

A plan that ignores focus, energy level, or task type is not a realistic one.

Plans often assume people work on one thing at a time. In practice, they rarely do.

One person might be assigned to:

• - Two projects
• - Three clients
• - Ongoing support
• - Plus “just a small task” here and there

Each switch comes with a cost. Time is lost in every change of context that happens daily. If availability doesn’t reflect this reality, it’s being overestimated.

Vacations, sick days, training, and public holidays are all handled as “exceptions.”

But they’re not exceptional. They’re normal.

When availability is calculated based on a “perfect” month, any absence will create pressure. As such, team members end up compensating by working longer or cutting things short.

A more realistic approach is to consider and plan around absences.

Forecasts often assume today’s availability will still apply next month.

But availability changes:

• - Priorities shift
• - New requests appear
• - Urgent work shows up
• - People burn out or slow down

When forecasts ignore these dynamics, they fail to really prepare you for what’s ahead.

Another challenge is that availability is often calculated per person, not across the team.

You might have:

• - One person overloaded
• - Another underutilized
• - And still miss deadlines

Why? Because skills, dependencies, and timing matter.

Availability isn’t just “who has time,” but who can do the work, when, and without blocking others.

Without this view, capacity problems are not truly visible.

Instead of asking:
“How many hours do we have?”

Try asking:

• - How much focused time do people really have?
• - What’s competing for their attention in the background?
• - Where do most interruptions come from?
• - What kind of work needs continuity to make progress?
• - What are we assuming about the weeks ahead?

Even small changes here can make planning more grounded.

For example:

• - Planning at 70–80% availability instead of 100%
• - Reserving time for meetings, coordination and support
• - Reviewing availability assumptions regularly.

Why is this important?

When teams consistently feel behind despite “reasonable plans,” the issue is the model.

Making availability visible, realistic, and adaptable with tools like CapaPlanner won’t fully eliminate surprises, but it will make most of them predictable or manageable.