The Flex Duct Cutter features a double edged knife blade that cleanly pierces through the outer skin, insulation and liner of flexible round duct. The blade cuts both directions, from any angle, around the entire duct circumference. The duct's exposed wire rib coil is then positioned in the jaws of a built-in wire cutter. A thumb operated latch releases the handles of the Flex Duct Cutter tool and opens the wire cutter jaws. The wire cutting feature completes the duct cutting job by severing the hardened wire rib. Routine oiling of working parts resists corrosion. Vinyl grips with hand stops provide added comfort and resistance to elements.