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Collaborative Robot Fleet Sizing Calculator

The Collaborative Robot Fleet Sizing Calculator estimates how many cobots are needed to handle a target number of task cycles during a shift. It combines required workload, average cobot cycle time, shift length, and productive utilization, then rounds the result up to a whole-unit fleet.

The estimate is useful for workstation planning where collaborative robots share or sequence work with people. It gives an initial capacity check before more detailed analysis of human interaction, safety-rated speed limits, handoffs, changeovers, and workstation balance.

Inputs

tasks
sec
hours
%
Result
—
Required cobot fleet
Capacity per cobot—
Estimated fleet capacity—
Productive minutes per cobot—

1. Enter required workload
Use the number of completed collaborative task cycles needed during the shift.

2. Enter average cobot cycle time
Use the full average cycle for the cobot portion of the work, including normal handoff or wait time if it occupies the cobot.

3. Set shift length
Enter the scheduled hours available to the collaborative workstation.

4. Set productive utilization
Account for breaks in robot work, changeovers, material waits, safety-related slowdowns, and other recurring losses.

5. Review the rounded fleet size
The estimate rounds up to enough whole cobots to meet the modeled task requirement.

Capacity per cobot = (Shift hours × 3,600 ÷ Cycle seconds) × Utilization; Required cobots = Ceiling(Required tasks ÷ Capacity per cobot)

Required tasks — target collaborative task cycles per shift.

Cycle seconds — average seconds per completed cobot cycle.

Shift hours — scheduled workstation time.

Utilization — productive share of scheduled time.

Required cobots — whole units needed to meet the modeled demand.

Assumptions: The calculation assumes similar cobots and divisible work. It does not model human pacing, ergonomic constraints, safety speed reductions by zone, quality losses, or task precedence in detail.

What the result means

Two cobots provide enough modeled cycle capacity for the 720-task requirement. The collaborative workstation should still be validated for human pacing and safety-rated operating conditions.

Use the result as a planning estimate and validate assumptions with observed operating data before making deployment decisions.

Given
• 720 required tasks per shift
• 55-second average cobot cycle
• 8-hour shift
• 72% productive utilization

Calculation
Capacity per cobot = (8 × 3,600 ÷ 55) × 0.72 = 376.93 tasks
Raw fleet need = 720 ÷ 376.93 = 1.91 cobots
Rounded requirement = 2 cobots

Result
2 cobots.

Interpretation
Two cobots provide enough modeled cycle capacity for the 720-task requirement. The collaborative workstation should still be validated for human pacing and safety-rated operating conditions.

Why can collaborative cycle time be longer than robot-only motion time?

A collaborative cycle may include waiting for a person, shared-zone speed limits, handoffs, or confirmation steps. Use the cycle time that reflects the actual workstation process.

Does utilization include operator breaks?

Only if the cobot cannot productively work during those periods. Set utilization to reflect the recurring availability of the combined workstation, not just the robot hardware.

Can one cobot serve several operators?

Possibly, but this calculator does not schedule multiple human-cobot interactions. Use an average cycle that reflects the intended workflow or model each station separately.

Why is safety not an input?

Safety affects layout, speed, force limits, and operating mode, but it cannot be reduced to one universal percentage. Incorporate safety-related effects in validated cycle time and utilization, then perform a proper risk assessment separately.

When is a task-capacity estimator more useful?

Use task capacity when the cobot count is already known and you want estimated output. Use fleet sizing when required output is known and cobot count is the unknown.