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Work Capacity Calculator

Work out how many people a workload needs, including headroom.

About Work Capacity Calculator

Rated capacity is a ceiling, not a design point, so it is derated by the headroom percentage before dividing. The result is rounded up because you cannot deploy a fraction of a person. Sizing to rated capacity leaves nothing for peaks or failures; the spare-capacity line shows whether the rounded-up count actually buys useful work capacity.

Formula

Work Capacity

Units = ⌈demand ÷ (capacity per unit × (1 − headroom))⌉

Hours of work to deliver per month
Total load to be served
Productive hours per person per month
Rated capacity of a single person

Worked example

With the default values below, Work Capacity Calculator returns Persons Required of 25. Change any input above and every figure here is recalculated in your browser.

Inputs used

Hours of work to deliver per monthminimum 0
2,400
Productive hours per person per monthminimum 0
120
Headroom reserved for peaksaccepts 0–100 %
20 %

Results

Persons Required
25
Exact Requirement Before Rounding
25.000
Usable Capacity per Person
96.000
Spare Capacity at That Count
0.0%
Total Usable Capacity Provisioned
2,400.00

Step by step

  1. 1Values used
  2. 2Work Capacity
  3. 3Persons Required= 25
  4. 4Exact Requirement Before Rounding= 25.000
  5. 5Usable Capacity per Person= 96.000
  6. 6Spare Capacity at That Count= 0.0
  7. 7Total Usable Capacity Provisioned= 2,400.00

Assumptions and limits

  • The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

How is Work Capacity calculated?

Units = ⌈demand ÷ (capacity per unit × (1 − headroom))⌉ Rated capacity is a ceiling, not a design point, so it is derated by the headroom percentage before dividing. The result is rounded up because you cannot deploy a fraction of a person.

Why does Work Capacity matter?

Sizing to rated capacity leaves nothing for peaks or failures; the spare-capacity line shows whether the rounded-up count actually buys useful work capacity.

What values do I need to enter?

This calculator takes 3 inputs: Hours of work to deliver per month, Productive hours per person per month, Headroom reserved for peaks. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.

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Work Capacity Calculator – Calculate Persons Required