An electric field describes the force a charged object would feel at every point in space around a given charge distribution, and calculating that field directly from Coulomb's law means summing the individual contribution of every single charge present, a task that becomes hopelessly impractical for a distribution made up of billions of charges. Gauss's law offers a genuine shortcut: it relates the total electric field passing through any closed surface to the total charge enclosed inside that surface, letting physicists calculate a field directly from a symmetric charge distribution's total enclosed charge without ever summing an individual charge's contribution.
Gauss's law connects a field's flux through a surface to what's inside it
Gauss's law states that the total electric flux, a measure of how much field passes outward through a closed surface, equals the total enclosed charge divided by a fixed physical constant, regardless of exactly how that charge is arranged inside the surface or how far the surface sits from it. This relationship holds for any closed surface at all, an oddly shaped balloon, a cube, a sphere drawn purely mathematically in empty space, which makes it a genuinely general law about how electric fields relate to their charge sources, not a formula tied to any one particular geometric configuration.
Choosing the right symmetric surface turns Gauss's law into a genuine shortcut
Gauss's law becomes practically powerful specifically when a charge distribution has real geometric symmetry, spherical, cylindrical or planar, because a physicist can then choose a matching closed surface, a sphere around a spherical charge, say, over which the electric field's strength is identical at every point, letting the flux calculation collapse into simple algebra rather than a genuinely difficult integral. For a distribution without that kind of exploitable symmetry, Gauss's law remains true but stops being a practical shortcut, which is exactly why the two most common ways of calculating an electric field, direct summation via Coulomb's law and Gauss's law, tend to get reached for in quite different situations depending on how symmetric the underlying charge distribution actually is.
What we're still unsure about
That Gauss's law holds universally for any closed surface, and that it becomes a practical calculational shortcut specifically for symmetric charge distributions, are well established, rigorously confirmed principles of classical electromagnetism. What's more genuinely a matter of pedagogical framing is exactly how early a physics course should introduce Gauss's law relative to Coulomb's law, since the two are mathematically equivalent, each derivable from the other, and educators continue to make different choices about which one to present as more fundamental, a decision that reflects teaching judgement about building intuition rather than any actual disagreement about the underlying physics.
This sits inside Electric Fields & Gauss's Law, one of eight topics in Electromagnetism, one of five domains in Physics, one of seventeen subjects the app can quiz you on.