A manifold for the distribution of a fluid in a plumbing and heating system has a tubular shape and defines in its interior a distribution conduit for the fluid. The manifold extends between a first inlet/outlet end and a second inlet/outlet end, both of which are designed to put the distribution conduit in communication with the exterior of the manifold to receive incoming fluid or to send fluid exiting the manifold. The manifold comprises a plurality of branches arranged in series along a longitudinal extension and interposed between the first and second inlet/outlet ends, wherein each branch allows a quantity of fluid to enter into or exit from the distribution conduit. Each branch is provided with an access or exit opening having a respective axis, and the branches are positioned in the manifold in such a way that: the distance between the first inlet/outlet end and the axis of the first branch is equal to an initial stretch, the centre-to-centre distance between the axis of each branch and the axes of the adjacent branches is equal to a centre-to-centre distance measurement between the branches, and the distance between the axis of the last branch and the second inlet/outlet end is equal to a final stretch. The length of the final stretch is equal to the sum of the length of the initial stretch and half of the centre-to-centre distance measurement.