A method in a base station for selecting a transport format is provided. The base station allocates resources to a User Equipment, UE.When a first criterion is fulfilled for the allocated resources, the base station estimates Signal-to-Interference-plus-Noise Ratio, SINR, by using a first gain offset. The first gain offset relates to a resource allocation according to the first criterion.When a second criterion is fulfilled for the allocated resources, the base station estimates SINR by using a second gain offset. The second gain offset relates to a resource allocation according to the second criterion.The base station then selects a transport format for the allocated resources based on the estimated SINR.