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Generator Load Calculator

Check generator loading and whether it sits in the healthy operating band.

About Generator Load Calculator

Diesel generators want to run between about 50 and 80 per cent of rating. Persistent light loading causes incomplete combustion, carbon deposits and eventually damage. Oversized standby sets that exercise on light load are a common source of failures, which load banks are used to avoid.

Formula

Generator Load

Loading % = demand kVA ÷ generator kVA × 100

wet stacking
Unburnt fuel accumulating when a diesel runs persistently light-loaded

Worked example

With the default values below, Generator Load Calculator returns Generator Loading of 46.67%. Change any input above and every figure here is recalculated in your browser.

Inputs used

Generator ratingminimum 0.01 kVA
60 kVA
Connected loadminimum 0 kW
28 kW
Load power factoraccepts 0.1–1
0.85
Diversity factoraccepts 0–100 %
85 %

Results

Generator Loading
46.67%
Actual Demand
28.000 kVA
Available Real Power
51.000 kW
Spare Capacity
27.200 kW
Verdict
Lightly loaded but acceptable

Step by step

  1. 1Values used
  2. 2Generator Load
  3. 3Generator Loading= 46.67
  4. 4Actual Demand= 28.000 kVA
  5. 5Available Real Power= 51.000 kW
  6. 6Spare Capacity= 27.200 kW
  7. 7Verdict= Lightly loaded but acceptable

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax 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 Generator Load calculated?

Loading % = demand kVA ÷ generator kVA × 100 Diesel generators want to run between about 50 and 80 per cent of rating. Persistent light loading causes incomplete combustion, carbon deposits and eventually damage.

Why does Generator Load matter?

Oversized standby sets that exercise on light load are a common source of failures, which load banks are used to avoid.

What values do I need to enter?

This calculator takes 4 inputs: Generator rating, Connected load, Load power factor, Diversity factor. 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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