This invention relates to a device for determining the conversion power of conversion element, a method for performing these measurements and a method for producing pcLEDs with essentially the same color point applying said device and said method. The device comprises a light source (5), a sample holder (6) and a detector element (7), wherein the light source (5) illuminates the sample holder (6) with a primary light (41), the sample holder (6) is at least locally transparent for a primary light (41), suitable to mount the multitude of conversion elements (3) capable to partly convert the primary light (41) into a secondary light (42), and comprises suitable prevention means (62, 62a, 62b, 62c, 62d, 62e) to prevent a light guiding of the secondary light (42) from one mounted conversion element (3) through the sample holder (6) to another mounted conversion element (3), and the detector element (7) is suitable to measure the intensities of primary and secondary light (41, 42) for each conversion element (3) separately.