Maximum-demand terminology

Demand Factor vs Diversity Factor: Electrical Load Planning Explained

Load-planning guide · Reviewed 22 Sep 2026 · ElectroDesigner

Demand factor and diversity factor are not two names for the same number. Demand factor compares a group's maximum coincident demand with its connected load. Diversity factor compares the sum of individual maximum demands with the maximum coincident demand of the group. Mixing the terms can hide an assumption or apply the same reduction twice.

In this article1. Definitions 2. Relationship 3. Worked example 4. Where each factor belongs 5. Assumptions and limits

1. Demand, coincidence and diversity

Demand factor relates maximum coincident demand to connected load:

Demand factor = Maximum coincident demand / Total connected load

Under this definition the factor is between 0 and 1.

Coincidence factor relates the group's simultaneous maximum demand to the sum of the individual maximum demands:

Coincidence factor = Group coincident maximum / Σ(individual maximum demands)

Diversity factor is the reciprocal relationship:

Diversity factor = Σ(individual maximum demands) / Group coincident maximum

Under the formal definition, diversity factor is at least 1. In industry practice, however, the phrase “diversity factor” is sometimes used informally for a simultaneity/coincidence factor below 1. For traceable engineering work, write the equation next to the factor so the intended meaning is unambiguous.

2. Why demand factor and diversity factor differ

Demand factor starts from connected load. Diversity starts from the individual maximum demands of several subdivisions. Those denominators are not the same.

Practical rule: if your load schedule already applies demand factors to create realistic subgroup maximum demands, do not apply a second generic “diversity” reduction unless it represents a separate, justified non-coincidence between those subgroup maxima.

3. Worked example

Assume three feeder groups have connected loads of 50 kW, 40 kW and 30 kW. Their individually assessed maximum demands are 40 kW, 30 kW and 20 kW. The measured or engineered maximum coincident demand of the combined group is 70 kW.

Total connected load = 50 + 40 + 30 = 120 kW

Σ individual maximum demands = 40 + 30 + 20 = 90 kW

Group demand factor = 70 / 120 = 0.583

Coincidence factor = 70 / 90 = 0.778

Diversity factor = 90 / 70 = 1.286

The three numbers describe different relationships. Calling 0.583 a diversity factor, or applying 0.778 on top of a schedule that already embeds the same non-coincidence, would obscure the calculation basis.

Build a Load Schedule with explicit demand factors

4. Where each factor belongs

Demand factor: useful when converting a connected load or load group into an estimated maximum demand.
Coincidence factor: useful when combining independently assessed subgroup maximum demands that do not peak at the same time.
Diversity factor: the reciprocal expression of that group non-coincidence under the formal definition.

The correct value is not determined by the formula alone. It comes from the applicable standard or guide, utility requirements, measured load profiles, operating sequence, load-management controls or a documented project assumption.

5. Assumptions and limits

Terminology differs between jurisdictions and company standards; always define the equation used.
Published example factors are not automatically transferable to another building type, process or country.
Coincidence can vary by season, operating mode and control strategy.
Demand/diversity calculations do not replace motor-starting, harmonic, phase-balance or transient studies.
For EV charging, data centers and other actively managed loads, the control strategy can materially change the coincident maximum and should be modelled explicitly.

Adjacent checks

Start with Connected Load vs Demand Load for the row-by-row schedule method. Use the Three-Phase Power Calculator to verify current conversion and the Generator Sizing Calculator when maximum demand becomes a source-sizing input.

Engineering references

Definition references: Schneider Electric Electrical Distribution Fundamentals Design Guide — Load Planning and Electrical Installation Guide — estimation of actual maximum kVA demand. Because industry terminology is inconsistent, this article states the equation explicitly rather than relying on the factor label alone.