Demand Load Calculator

Feeder and service sizing starts from one question: what is the highest load the installation actually pulls at once? Not the sum of every rating - the demand, after the daily rhythms of each category are discounted.

Demand Load Calculator applies editable demand factors per category, then an optional diversity factor to the total, and returns the demand kW and kVA with a clear breakdown for feeder and service work.

It is a preliminary planning aid; final sizing follows the statutory method in force.

• Six load categories: Lighting, sockets, appliances, HVAC, motors, other.
• Editable demand factors: Per-category, pre-filled with typical values.
• Diversity factor: On the total, for staggered peaks.
• Power factor: Converts demand kW to the kVA a feeder carries.
• Per-category breakdown: Each contribution shown and exportable.
• Export: Copy or download as text, CSV or JSON.
• Learning guide: Demand vs diversity made clear.

1. Enter each connected load in kW.
2. Adjust the demand factor to the building habit.
3. Set the diversity factor for the total.
4. Enter the power factor of the load mix.
5. Read the demand kW and kVA for feeder sizing.
6. Export the breakdown if needed.

Example 1 — Commercial. 100 kW connected, factors 0.5/0.4/0.8/0.9/0.8/0.5 give about 66 kW demand; at 0.85 pf that is 78 kVA for the service.

Example 2 — Diversity. Adding a 0.9 diversity to the same total gives 59.4 kW — a smaller main feeder.

Example 3 — Mixed. Lighting peaks evening, HVAC peaks midday; their combined demand is far below the sum of both peaks.

Example 4 — Motor. Pumps at 0.75 factor with start surges planned into the feeder.

• Right service size: Demand, not inflated nameplate totals.
• Transparent maths: Every factor contribution visible.
• Editable rules: Match the building, not a fixed default.
• Feeder-ready: kW and kVA both delivered.
• Free and private: No uploads, no accounts, no logging.