Maximum Demand Calculator

Calculate maximum demand for electrical installations. Enter circuit loads and demand factors. Get total connected load, MD, and overall demand factor. Based on standard electrical engineering practices. Informational only—consult a qualified electrician.

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Published: October 23, 2025 | Updated: October 23, 2025 | Reviewed by: Science/Engineering Editor

⚠️ Professional Guidance Required: This calculator provides estimates. All electrical work must comply with local regulations and be performed by licensed professionals.

Installation Parameters

Circuits

Circuit Name Load (kW) Demand Factor Demand (kW) Action

Preset Installations

Typical Demand Factors

Load TypeTypical Demand Factor
Lighting (Residential)0.5 - 0.7
General Outlets (Residential)0.5 - 0.7
HVAC (Residential)1.0
Commercial Lighting0.7 - 0.9
Commercial Power0.7 - 0.9
Industrial Motors0.6 - 0.8

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How it works

Maximum Demand = Σ (Load × Demand Factor). We multiply each circuit's load by its demand factor and sum them up to find the total maximum demand for the installation.

The overall demand factor represents the diversity of the load and is calculated as the ratio of maximum demand to connected load.

Inputs explained

  • Load Type: Choose between kW (kilowatts) or kVA (kilovolt-amperes)
  • Circuit Name: Descriptive name for each circuit
  • Load: The connected load for each circuit
  • Demand Factor: A value between 0 and 1 representing the expected utilization

Example

Scenario: Simple Residential Installation

  • Circuit 1 (Lighting): 10 kW, DF = 0.8 → Demand = 8 kW
  • Circuit 2 (Outlets): 5 kW, DF = 1.0 → Demand = 5 kW
  • Total Connected Load: 15 kW
  • Total Maximum Demand: 13 kW
  • Overall Demand Factor: 86.7%

Tips & notes

  • Demand factors account for the fact that not all loads operate at their full rated capacity simultaneously
  • The overall demand factor is a measure of the diversity of the load
  • These calculations are essential for sizing service conductors and protective devices
  • Always consult local electrical codes for specific requirements
  • Different types of loads have different typical demand factors

FAQs

The peak load that an electrical installation is expected to carry.

A factor applied to a load to estimate its contribution to the maximum demand. It ranges from 0 to 1.

Total Maximum Demand / Total Connected Load, expressed as a percentage.

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Disclaimer

Informational tool based on standard electrical engineering practices. Must comply with local regulations. Consult a qualified electrician for official calculations and installations.

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