A butterfly bolt is a light-duty hollow-wall fastener built from two main parts, a spring-loaded pair of wings and a threaded machine screw. It exists to solve one very specific problem: how do you hang something heavy on a wall when there is no solid stud, joist or masonry directly behind the mounting point? Ordinary screws simply pull out of hollow drywall or plaster under load, so the butterfly bolt spreads the weight across a much wider area on the hidden side of the wall instead of relying on a single point of contact.
The name comes directly from its shape. When the two wings are folded flat against the shaft, the bolt slides through a drilled hole with ease. Once it clears the far side of the wall, a small internal spring snaps the wings outward into a shape that closely resembles an open butterfly, which is why the fastener is known by several interchangeable names across the hardware industry, including toggle bolt, butterfly anchor and spring toggle.
It is worth separating this wall-anchor style of butterfly bolt from a second, unrelated product that shares the same name: the wing bolt, sometimes called a butterfly screw or thumb screw. That is a hand-tightened fastener with two flat wings on its head, designed for tool-free assembly on tripods, RTA furniture and equipment panels rather than for anchoring into hollow walls. Both products get called a butterfly bolt in everyday conversation, so this guide covers the wall-anchoring toggle version in depth and explains the wing-screw variant separately in the types section below.
Where Butterfly Bolts Are Used
Because the anchor distributes weight rather than concentrating it, a butterfly bolt shows up anywhere a homeowner, electrician or installer needs to mount something onto a hollow surface. Typical jobs include hanging floating shelves, securing bathroom mirrors, mounting curtain rods and blinds, installing light fixtures and ceiling fans on plaster ceilings, fixing wall-mounted cabinets in kitchens and laundry rooms, attaching towel bars and grab-adjacent fixtures, and mounting gym equipment such as pull-up anchors or resistance band brackets to interior walls.
Butterfly Bolt vs. a Standard Wall Screw
A standard wood screw or drywall screw relies on friction against the thin paper and gypsum layers of the wall, which is only strong enough for lightweight picture frames. A butterfly bolt instead reaches through the wall cavity and locks against the back face of the drywall sheet itself, turning a thin, brittle surface into a load-bearing anchor point. This is the core reason butterfly bolts are specified whenever the item being hung exceeds a few pounds.
