An indexable cutting insert for a milling tool, the cutting insert comprising: an upper side defining an upper extension plane (Pu); a lower side defining a lower extension plane (P L) parallel to the upper extension plane (Pu); wherein a centre axis extends perpendicularly through the upper extension plane (Pu) and the lower extension plane (P L); a side surface connecting the upper side and the lower side, the side surface comprising a plurality of upper main clearance surfaces and secondary clearance surfaces (6, 6a, 6b); and at least six identical and alternately usable upper cutting edges extending around the upper side, wherein each cutting edge comprises a chip removing main cutting edge portion and at least one secondary cutting edge portion (9, 10), wherein the main cutting edge portion is formed in a transition between the upper side and one of said upper main clearance surfaces, wherein the at least one secondary cutting edge portion (9, 10) is formed in a transition between the upper side and one of said secondary clearance surfaces (6, 6a, 6b) in a region between two main cutting edge portions, and wherein each of said upper main clearance surfaces is formed at an obtuse inner angle α with respect to the upper extension plane (P U) as seen in side elevation view, wherein the main cutting edge portion is inclined as seen in side elevation view of the cutting insert so that the main cutting edge portion is declining with respect to the upper extension plane (P U) in a direction toward an end of the main cutting edge portion, wherein each of said secondary clearance surfaces (6, 6a, 6b) is formed at an inner angle β with respect to the upper extension plane (P U) as seen in side elevation view, wherein β < α, wherein an end portion of the main cutting edge portion is located below a successive secondary cutting edge portion (9, 10) of the at least one secondary cutting edge portion (9, 10) with respect to the upper extension plane (Pu), wherein the end portion of the main cutting edge portion is connected to an ascending transition edge connected to the successive secondary cutting edge portion (9, 10), wherein the at least one secondary cutting edge portion (9, 10) is in the form of a surface-wiping secondary edge, characterized in that the inner angle α between the upper extension plane (Pu) and each of said upper main clearance surfaces is within the range 98° ≤ α ≤ 118°, and that the inner angle β between the upper extension plane (Pu) and the secondary clearance surface (6, 6a, 6b) below at least a part of the at least one secondary cutting edge portion (9, 10) is within the range 85° ≤ β ≤ 100°. an upper side defining an upper extension plane (Pu); a lower side defining a lower extension plane (P L) parallel to the upper extension plane (Pu); wherein a centre axis extends perpendicularly through the upper extension plane (Pu) and the lower extension plane (P L); a side surface connecting the upper side and the lower side, the side surface comprising a plurality of upper main clearance surfaces and secondary clearance surfaces (6, 6a, 6b); and at least six identical and alternately usable upper cutting edges extending around the upper side, wherein each cutting edge comprises a chip removing main cutting edge portion and at least one secondary cutting edge portion (9, 10), wherein the main cutting edge portion is formed in a transition between the upper side and one of said upper main clearance surfaces, wherein the at least one secondary cutting edge portion (9, 10) is formed in a transition between the upper side and one of said secondary clearance surfaces (6, 6a, 6b) in a region between two main cutting edge portions, and wherein each of said upper main clearance surfaces is formed at an obtuse inner angle α with respect to the upper extension plane (P U) as seen in side elevation view, wherein the main cutting edge portion is inclined as seen in side elevation view of the cutting insert so that the main cutting edge portion is declining with respect to the upper extension plane (P U) in a direction toward an end of the main cutting edge portion, wherein each of said secondary clearance surfaces (6, 6a, 6b) is formed at an inner angle β with respect to the upper extension plane (P U) as seen in side elevation view, wherein β < α, wherein an end portion of the main cutting edge portion is located below a successive secondary cutting edge portion (9, 10) of the at least one secondary cutting edge portion (9, 10) with respect to the upper extension plane (Pu), wherein the end portion of the main cutting edge portion is connected to an ascending transition edge connected to the successive secondary cutting edge portion (9, 10), wherein the at least one secondary cutting edge portion (9, 10) is in the form of a surface-wiping secondary edge, characterized in that the inner angle α between the upper extension plane (Pu) and each of said upper main clearance surfaces is within the range 98° ≤ α ≤ 118°, and that the inner angle β between the upper extension plane (Pu) and the secondary clearance surface (6, 6a, 6b) below at least a part of the at least one secondary cutting edge portion (9, 10) is within the range 85° ≤ β ≤ 100°.