A heat exchanger may include a heat exchanger block that may have a plurality of pipes and at least one collector. The at least one collector may include at least one pipe end that may accommodate the plurality of pipes in a leakproof manner at a longitudinal end thereof. The heat exchanger may include a terminal piece that may have a duct structure. The duct structure may include a plurality of webs that may separate a plurality of ducts situated between the plurality of webs from each other. The plurality of webs may include a web width bS of 1.0 mm