How to forecast workload for the next 3 months

What a 3-month workload forecast is 

A 3-month workload forecast is a forward-looking estimate of the amount of work a team is expected to handle over the next quarter and whether current capacity can support it.

It helps answer questions such as:

• Are we likely to overload the team in the next few months?
• Do we need to move timelines or adjust scope?
• Will upcoming work require additional capacity?

At this horizon, the forecast focuses on trends and risks rather than precise scheduling.

What inputs you need for a 3-month forecast

A reliable forecast requires a small set of consistent inputs.

1. Planned and probable work 

Include:

• Confirmed projects and initiatives
• High-confidence upcoming work
• Recurring operational commitments

Some teams also include likely pipeline work as a separate scenario.

2. Rough effort estimates 

Effort should be estimated:

• At project or role level
• In ranges rather than exact hours
• With consistent assumptions across projects

Precision is less important than comparability.

3. Team availability 

Account for:

• Weekly working hours
• Part-time schedules
• Planned vacations and holidays
• Non-project commitments

This defines realistic capacity over time.

4. Time buckets 

Most teams forecast using:

• Monthly buckets for a 3-month horizon
• Sometimes, a weekly detail for the first month

This balances clarity with effort.

Step-by-step workload forecasting process 

A practical process looks like this:

Step 1: List expected work 

Capture all known and likely work for the next three months.

Step 2: Estimate demand per period 

Distribute effort across months based on delivery timing rather than exact task plans.

Step 3: Calculate available capacity 

Sum available capacity per role or team after time off and non-project work.

Step 4: Compare demand and capacity 

Look for:

• Sustained overload in specific months
• Underutilized capacity
• Dependency on a small number of people

Step 5: Create scenarios 

Test assumptions such as:

• Delaying lower-priority work
• Adding or removing projects
• Temporary capacity increases

Scenarios help teams prepare instead of react.

How detailed a 3-month forecast should be 

At three months out, forecasts should:

• Stay at project or role level
• Avoid task-by-task planning
• Focus on direction and risk
• Be easy to update

Over-detail increases effort without improving accuracy.

Common workload forecasting mistakes 

Teams struggle when they:

• Treat forecasts as fixed commitments
• Ignore non-project work
• Assume all pipeline work will close
• Keep forecasts static for too long
• Try to be precise too early

Forecasts should evolve as information improves.

When a 3-month forecast is most useful

This type of forecast is especially valuable when:

• Multiple projects overlap
• Hiring decisions depend on near-term demand
• Teams experience frequent plan changes
• Leaders need visibility beyond the next few weeks

It creates a bridge between short-term execution and longer-term staffing decisions.

Frequently asked questions 

How accurate should a 3-month workload forecast be?

It should be directionally accurate. The goal is to identify trends and risks, not predict exact hours.

 

Should teams include pipeline or tentative work?

Yes, but as separate scenarios. This avoids overcommitting while still planning for likely outcomes.

 

How often should a 3-month forecast be updated?

Most teams update it monthly, or whenever major priorities or timelines change.

Sources

PMI library: Forecasting and resource planning concepts
https://www.pmi.org/learning/library/resource-leveling-scheduling-projects-6007

Atlassian: Workload forecasting and capacity planning
https://www.atlassian.com/work-management/project-management/workload-management

IBM: Capacity and workload planning
https://www.ibm.com/topics/capacity-planning

Planta glossary: Workload forecasting explained
https://plantapp.io/glossary/workload-management/