Apparatuses, methods, and systems are disclosed for uplink transmission power allocation. One method includes receiving a configuration of two uplink carriers. The method includes determining whether a configuration parameter corresponding to at least one of a first uplink carrier and a second uplink carrier for a serving cell is configured. The method includes determining whether a power headroom report is based on an actual sounding reference signal (“SRS”) transmission or a reference SRS transmission. The method includes, in response to determining that the power headroom report is based on a reference SRS transmission, selecting an uplink carrier for power headroom computation from the two uplink carriers based on whether the configuration parameter for the two uplink carriers. The method includes computing the power headroom report for the serving cell based on a reference SRS transmission on the uplink carrier.