The present castle consists of two wings build in an angle. The surface is plastered and whitewashed in a distinct red colour.
The castle has 3 floors and a basement. Placed in the corner of the two wings, tt has an octagonal tower with a spire. The courtyard faces the park and lake.
The north wing has parts dating back to the 12th century which makes Tranekaer the oldest non-clerical lived in house in Denmark. In the basement, building debris from the very early middle ages was found. That makes the castle even older.
The castle was surrounded by a moat, which still exists today. West of the castle the main road runs on top of a dam that keeps the water in the moat and lake. The water drains west by the old water mill(Skvatmøllen).
In the 16th century the castle consisted of a large center tower, the two present wings and two lower wings on the east and south side, which were torn down in the early 18th century.
The mighty tower was demolished in the middle of the 17th century almost a 100 years after having lost its military importance in 1558.
Both the present wings have walls up to 13 feet(4m) thick and in the west wing there is a parapet walk inside the wall itself.
The present shape of the castle is due to a major conversion initiated by Count Frederik Ahlefeldt-Laurvig in the years 1859-1862. In charge of this undertaking was the architect and professor N.S. Nebelong. He extended the west wing, the tower was build, rooms were added in the attic, with windows. The whole building was plastered and whitewashed in a pale red allmost pink colour. Windows and doors were painted brown.
In 1947-1949 the castle was restored again, this time ending up with the present colour (english red) and woodwork painted white.