What is a travel day?
You can buy a pass with either 3, 4, 5, 6, 7 or 10 travel days. A travel day lasts for 24 hours, from 12 midnight on one day to 12 midnight of the following day. On each travel day you can take as many trains as you want. The travel days can be used within a 1 month period.
An exception is the 7 p.m. rule. If you board a direct night train that departs after 7 p.m. and arrives after 4 a.m. the next day, then only the day of arrival is counted as a travel day. On your German Rail Pass, you should write the day of arrival on the pass prior to boarding the night train. The day of arrival will then be counted as your travel day and the day of departure is not counted.
The 7 p.m. rule only applies after the activation date of your pass. For example, if your German Rail pass is activated from August 6, you cannot use the 7 p.m. rule on the evening of August 5.