Kilogram Exponent (KGE)

Kilogram Exponent (KGE) is the value Xert uses to show how much rider weight matters for performance on a given terrain. Higher KGE = weight matters more (steeper climbing). Lower KGE = weight matters less (flatter or descending). 

Definition

Kilogram Exponent (KGE) is the exponent used in Xert’s Relative Power calculations. It changes based on the gradient of the terrain. 

A quick way to think about it:

• Steeper terrain → higher KGE → W/kg matters more
• Flatter terrain → lower KGE → raw watts matter more 

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What It Means

KGE helps Xert “blend” between watts and watts/kg:

• When KGE = 1, Relative Power behaves like Watts/kg
• When KGE = 0, Relative Power behaves like Watts 

So as the road tilts up, body weight plays a bigger role; as it flattens out, weight matters less. 

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How Xert Uses It

KGE in Relative Power

Xert uses KGE to estimate what power a standard 75 kg rider would need to match your effort on that terrain. 

Average KGE for an activity

Xert calculates an activity’s average KGE using a weighted average based on gradient and your power, so hard climbing influences KGE more than easy coasting downhill.  ou’ll See It

• In Race AI / performance modeling contexts where Xert is accounting for terrain and rider weight using Relative Power. 

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Related Terms

• Relative Power
• Race AI
• Xert Equivalent Power (XEP)