A cap for a container with a hinged lid comprising a first part and a second part snap-engaged with each other on assembly, wherein: - the first part comprises a cylindrical base body which provides a first lower cylindrical portion having a larger diameter and a second upper cylindrical portion with a smaller diameter , coaxial with respect to each other, wherein said first lower cylindrical portion having a larger diameter is internally threaded in , so that it can be positioned on a screw neck of a mouthpiece of a container and said second upper cylindrical portion with a smaller diameter forms the pouring part of the cap, - the second part comprises a covering lid which provides an annular portion below and a lid portion above and a hinge arrangement consisting of a strip is interposed between said annular portion and said lid portion , - wherein the strip comprises weakened foldable end areas , connected to said annular portion and to said lid portion respectively, and a folding invitation line , centrally arranged longitudinally in the strip which divides the strip into two and defines two portions between which a central recess is arranged, folding invitation lines also being provided (42,43,56 and 57) between said two portions and said annular portion so that said lid portion can be moved between a closed position above said first part and a completely open overturned position alongside said first part , characterized in that said strip is arranged in a window opening , which is formed in the side surface of the lid portion and which is open towards the annular portion , and folding invitation lines (46, 47, 58 and 59) are also arranged between said two portions and an end edge of said opening in said lid portion . - the first part comprises a cylindrical base body which provides a first lower cylindrical portion having a larger diameter and a second upper cylindrical portion with a smaller diameter , coaxial with respect to each other, wherein said first lower cylindrical portion having a larger diameter is internally threaded in , so that it can be positioned on a screw neck of a mouthpiece of a container and said second upper cylindrical portion with a smaller diameter forms the pouring part of the cap, - the second part comprises a covering lid which provides an annular portion below and a lid portion above and a hinge arrangement consisting of a strip is interposed between said annular portion and said lid portion , - wherein the strip comprises weakened foldable end areas , connected to said annular portion and to said lid portion respectively, and a folding invitation line , centrally arranged longitudinally in the strip which divides the strip into two and defines two portions between which a central recess is arranged, folding invitation lines also being provided (42,43,56 and 57) between said two portions and said annular portion so that said lid portion can be moved between a closed position above said first part and a completely open overturned position alongside said first part , said strip is arranged in a window opening , which is formed in the side surface of the lid portion and which is open towards the annular portion , and folding invitation lines (46, 47, 58 and 59) are also arranged between said two portions and an end edge of said opening in said lid portion . <EOS>