A multi-speed transmission has four planetary gear sets, eight rotatable shafts and six shifting elements. The sun gear of the first planetary gear set is connected to the third shaft. The input shaft is detachably connectable to the fourth shaft. The input shaft is connected to the sun gear of the fourth planetary gear set. The eighth shaft is connected to the ring gear of the first planetary gear set, the sun gear of the second planetary gear set, and the sun gear of the third planetary gear set. The fifth shaft is connected to the bar of the second planetary gear set and the ring gear of the third planetary gear set and is detachably connectable to the seventh shaft. The sixth shaft is connected to the ring gear of the second planetary gear set and is detachably connectable to the output shaft of the transmission.