We present an elementary proof establishing the equality of the right and left-sided $\sqrtκ$-quantum lengths for an SLE$_κ$ curve, where $κ\in (0,4]$. We achieve this by demonstrating that the$\sqrtκ$-quantum length is equal to the $(\sqrtκ/2)$-Gaussian multiplicative chaos with reference measure given by half the conformal Minkowski content of the curve, multiplied by $2/(4-κ)$ for $κ\in (0,4)$ and by $1$ for $κ=4$. Our proof relies on a novel "one-sided" approximation of the conformal Minkowski content, which is compatible with the conformal change of coordinates formula.