An exhaust flange is a device used to attach an exhaust pipe to an exhaust manifold or another piece of exhaust pipe.

Commonly designed to sandwich an exhaust gasket between the exhaust manifold and the exhaust pipe, the exhaust flange is manufactured to an exact angle to eliminate the chance of any exhaust leaks when tightened.

Nearly every type of exhaust, from manifolds to tubular headers, incorporates the exhaust flange in some form to prevent exhaust leaks. Some versions of the flange utilize what is known as a donut gasket to assist in sealing the system. The donut gasket is a round gasket that uses a flat and smooth center hole to ride solidly on the exhaust pipe. The outside diameter of the donut gasket is manufactured with a slight angel on each side that is sandwiched into the flange on the exhaust manifold and the exhaust pipe.