Bunsen Burner Flame Cone Angle Calculator
Reviewed by Hamza Gujjar, Algorithm Architect & Software Developer
Last updated: July 26, 2026Bunsen Burner Flame Cone Angle Calculator
The classic blue cone of a Bunsen burner flame is not an arbitrary shape - its angle is set by a simple velocity balance between how fast gas exits the burner and how fast the flame can burn back into it.
The Formula
sin(α) = SL / Vjet
Where α is the cone's half-angle, SL is laminar burning velocity, and Vjet is the unburned gas jet velocity leaving the burner tube.
Worked Example
A laminar burning velocity of 0.4 m/s with a jet velocity of 2.0 m/s: sin(α) = 0.4/2.0 = 0.2, giving α = 11.5°.
A Classroom Note
This relationship is a staple of introductory combustion demonstrations precisely because it is visible to the naked eye - turning up the gas valve (increasing jet velocity) visibly narrows and sharpens the cone, exactly as the formula predicts, without needing any instrumentation to observe the effect.
How to Use This Calculator
- Enter the mixture's laminar burning velocity.
- Enter the gas jet velocity leaving the burner tube (must be faster than the burning velocity, or no stable cone can form).