Multi-function pliers with tensioner and dynamometer comprised of a first lever made out of a main body the upper end of which having a semi-cylindrical formation with a structural wall, to which a second lever is mounted, the semi-cylindrical formation having a slit where the segment of a clamp is applied, an alignment wall that delimits an end of the semi-cylindrical formation being provided therein, said slit having a tooth; said second lever, comprised of a main body having a housing inside same where a spindle is mounted through a smooth orifice, a head being defined on the upper end portion of the body having an extruded linear profile that supports a circular base that receives the semi-cylindrical formation, an access snout being defined on the upper end position of the head the central portion of which defines a slit formation where the segment of a metal clamp is applied, and a tensioning handle is defined on the lower end portion of the spindle; a device for cutting the segment of the composed metal clamp by a pair of cutting blades and, each of them at one of the ends of each of said first lever and second lever, mainly where the access snout of the second lever and the slit of the first lever, respectively, are defined; a device for tensioning said metal clamp comprised of said spindle defined by a threaded longitudinal shaft mounted inside the housing of the second lever the free end of which passes through the smooth orifice defined in the inner end of the second lever and located inside the smooth orifice defined on the upper end portion of the main body; characterized by a carriage provided with traction pin of the segment of the metal clamp being defined along the spindle which carriage is comprised of a monolithic block having a threaded through-hole mounted next to the threaded longitudinal shaft of the spindle the upper external face of which defines a hook, by said handle being an anatomical rotatable handle mounted at the free end of the spindle; by a tension indicator of the tension of said clamp, comprised of a display located at the lower end of the second lever, provided with an oblong slit and tension graduation on one of its sides, so that in the region of said slit an indicating point is defined that is marked in the lower end of a compressive spring mounted on the lower housing defined in the internal end of said second lever and passing its inner diameter through the spindle and also delimited by the tensioning handle; and by a safety blocking device comprised of a smooth segment of the spindle without any thread extending from the spindle that passes through a first support that fits into the cavity of the second lever, the end of said smooth segment of the spindle forming a base of the spindle connected to the back portion of the base of a lock, a blocking pin that passes through the opening of a second support fit into the cavity of the second lever being orthogonally mounted on the front portion thereof, a return spring passing through the whole body of the blocking pin, a channel also being defined in the region of the semi-cylindrical formation of the first lever, the displacement of said blocking pin towards the interior of said channel causes a compression of said return spring and prevents said levers and from closing.