Valid for a single trip including one transfer on the whole length of lines 1-99, 101-299, 900-999, M1, M2, M3, M4 as well as on lines H5, H6, H7, H8, H9 only within the administrative boundaries of Budapest. Trip interruptions and return trips are not permitted. The ticket must be validated at the printed number grids at both ends each time you board: first when starting a trip at one end, and at the other end when transferring, except for transfers between metro lines M1, M2, M3 and M4. In case of tickets issued on thermopaper, please validate the tickets according to their numbering. When validated by a stamping machine, the total validity period is 100 minutes (on night services it is 120 minutes), with an 80-minute validity after the second stamping. When the second validation takes place at the entrance of a metro station, the validity is 80 minutes even if the whole trip exceeds 100 minutes. If the second stamped validation takes place on a night service, validity is extended an additional 120 minutes. Please show and hand over your ticket if requested by the inspector. Thermopaper transfer tickets are valid only if both sections are presented for control at the same time.
Please find more information here on the refund rule.