Diversity Factor Formula & Table
Introduction #
Instant answer: Demand factor = group maximum demand ÷ connected load and is normally ≤1. Diversity factor = sum of individual maximum demands ÷ coincident group maximum demand and is normally ≥1. Coincidence factor is its reciprocal. For an illustrative 682 kW connected inventory and 491 kW measured peak, the demand factor is 491/682 = 0.720; 682/491 = 1.389 is only the inverse demand factor, not a proven diversity factor unless 682 kW also equals the sum of the individual maximum demands.
Open Factory Load — 491 kW demand · PF 0.87 →
Decision gate: which diversity number to use #
| Decision | Use this | Do not |
|---|---|---|
| Existing facility demand baseline | Metered coincident maximum demand and the applicable load study | A copied factor from another plant |
| One MCC / machine group | Group demand factor for that group | Plant-wide coincident on every feeder |
| Healthcare / Tier IV / always-on | Near 1.0 (little diversity) | Aggressive diversity to shrink gear |
| Boundary | Code-stamped load studies, NFPA 99 | Spreadsheet factor without meter proof |
When this guide fits: You need to distinguish connected load, maximum demand, demand factor, diversity factor, and coincidence factor before using interval data in a planning study.
When it is not suitable: NFPA 99 healthcare, data center Tier IV, or any site where every load must ride through on nameplate—diversity assumptions differ.
Illustrative dataset: The numbers below show the calculation path; they are not a real facility record or a substitute for a code-compliant load study.
Two definitions people confuse #
| Term | Formula | Result from the illustrative data |
|---|---|---|
| Demand factor | Group maximum demand ÷ connected load | 491 ÷ 682 = 0.720 |
| Diversity factor | Sum of individual maximum demands ÷ coincident group maximum demand | Needs individual maxima; cannot be solved from 682 and 491 alone |
| Coincidence factor | Coincident group maximum demand ÷ sum of individual maximum demands | Reciprocal of diversity factor |
Do not rename connected-load ÷ demand as diversity factor. Connected load is a nameplate inventory; the numerator of diversity factor is the sum of individual maximum demands, which may be lower than connected load.
Schneider Electric's Electrical Installation Guide uses the same coincidence-factor definition and notes that diversity is its reciprocal; terminology is sometimes used inconsistently in practice, so always state the formula beside the factor.
Demand factor = Measured maximum demand ÷ Connected load
= 491 ÷ 682 = 0.720
Inverse demand factor = Connected load ÷ Measured maximum demand
= 682 ÷ 491 = 1.389
This inverse is not automatically a diversity factor.
Do not invert this when speaking to finance—show both numbers side by side.
Illustrative interval-demand screen #
| Step | Result |
|---|---|
| Nameplate inventory (connected) | 682 kW |
| Utility 15-min peak (30 days) | 491 kW |
| Demand factor | 0.720 |
| Inverse demand factor | 1.389 |
Interval demand is stronger evidence than a copied planning factor, but it still represents the observed period. Check season, shifts, process states, meter interval, abnormal outages, future loads, and the applicable electrical load calculation before sizing equipment.
Reproduce demand steps: Factory Load Calculator.
Group demand factors — same plant, by feeder #
These are illustrative demand factors (group demand ÷ group connected), not diversity factors:
| Load group | Connected kW | Group demand kW | Demand factor |
|---|---|---|---|
| Packaging lines 1–4 | 420 | 318 | 0.76 |
| Seal welders | 85 | 34 | 0.40 |
| Chillers + pumps | 95 | 72 | 0.76 |
| Lighting + controls | 48 | 44 | 0.92 |
| Offices | 34 | 23 | 0.68 |
Do not average these group factors. Sum loads on a common time basis or use the measured coincident site maximum.
Illustrative copied-factor error #
An intern applied textile industry 0.55 to 682 kW connected:
Wrong demand = 682 × 0.55 = 375 kW (vs 491 kW actual)
Result understates the illustrative measured peak of 491 kW
Correct approach:
Use metered demand 491 kW first
Document demand factor 0.720 for this observed period
Do not call the inverse 1.389 a diversity factor without individual maximum-demand data
Full trip narrative: Factory load calculation mistakes.
When textbook tables are OK (and when they are not) #
| Situation | Use tables? |
|---|---|
| Greenfield, no meter | Use the applicable code load calculation and documented process assumptions |
| Expansion on live plant | Meter first, tables only cross-check |
| Repeating process with interval data | Derive demand and coincidence from aligned timestamps |
| Intermittent loads | Use equipment duty records or submetered individual maxima; do not copy an industry percentage |
Apply diversity without double-counting #
Wrong:
Apply group factors → sum → apply another 0.85 "whole plant" factor
Right:
Option A: Metered utility peak (preferred)
Option B: Sum of group demands with non-coincident zones (HVAC guide method)
Connected vs demand primer: Connected Load vs Demand Load.
After kW is firm, convert with kW to kVA for transformer work in distribution design.
Browse Power calculator hub.
Related articles #
Technical source #
Next steps you should take #
- Export 30 days of interval kW; record the billing peak window.
- Sum connected nameplates the same week.
- Compute demand ÷ connected and file it as demand factor for the observed period.
- Compute diversity/coincidence only when individual maximum demands and the coincident group maximum share a defined period and measurement basis.
- Update assumptions after Line 5 expansion (page 2026-05-25).
How do you calculate diversity factor?
Divide the sum of individual maximum demands by the coincident group maximum demand over a defined study period. Connected nameplate load cannot replace the sum of individual maxima. With only 682 kW connected and a 491 kW site peak, you can calculate demand factor (491/682 = 0.720), not diversity factor.
How to calculate diversity factor in HVAC?
For HVAC, diversity applies to zone coincident cooling peaks, not electrical nameplates. Sum each zone’s peak kW at different times, then divide total connected HVAC kW by that coincident peak. Electrical diversity still needs its own meter proof—see our industrial HVAC design guide.
What is a diversity factor table used for?
A planning table is only an assumption source when measurements are unavailable. Confirm the table's definition and project scope: demand factor, diversity factor and coincidence factor are not interchangeable. Replace assumptions with aligned interval and equipment data when available.
Is diversity factor the same as demand factor?
No. Demand factor is maximum demand divided by connected load. Diversity factor is the sum of individual maxima divided by the coincident group maximum. Coincidence factor is the reciprocal of diversity factor.
Can coincidence factor be less than 1.0?
Yes. Coincidence factor is normally at or below 1.0 because the group peak usually occurs when not every component is at its individual maximum. Diversity factor is its reciprocal and is normally at or above 1.0.
How often should we recalculate?
After any line addition, seasonal product change, or shift schedule change—at least annually on industrial tariffs.
Does HVAC diversity match electrical diversity?
No—coincident cooling peaks use zone envelopes ([HVAC design](/guides/industrial-hvac-design)), but electrical demand still needs its own meter proof.
What if I only have nameplates today?
Use the applicable code load calculation plus documented process schedules and equipment duties. Plan metering so the assumptions can be checked after operation begins; do not copy a factor from another industry.