League of Legends Reaction Time Test | The Flash-Dodge Window

A 250 ms flash-dodge reaction is the difference between Diamond and Challenger on many champions. SERO measures that exact window.

Reaction Time in MOBAs Is Different

Unlike FPS, MOBA reaction is mostly about anticipation + dodge. The trainable layer is the cognitive commit between seeing a cast animation and pressing Flash.

Sub-250 ms = Climb Faster

Players who shave 30–50 ms off their flash-dodge window measurably climb faster in ranked. SERO benchmarks it in 90 seconds.

Test your flash window

FAQ

Will this help me climb?

It trains one of the highest-leverage cognitive skills in League — flash-dodge timing.

Is it free?

Yes, no signup, no install.

Is it allowed alongside League?

Yes — it is a separate browser page, not a client overlay.