On which night of Hanukkah are all eight branches of the menorah lit?

On which night of Hanukkah are all eight branches of the menorah lit? The answer is the eighth night.

Hanukkah is observed for eight nights, and the standard lighting custom adds one festival candle after each night. One candle is lit on the first night, two on the second, and the pattern continues until all eight festival branches are illuminated on the eighth night. A separate shamash is also usually lit to serve as the helper candle.

The arrangement reflects the practice associated with the school of Hillel, which became the accepted custom. The candles are generally placed from right to left, with the newest candle added at the left; they are then kindled from left to right, beginning with the newest light.

The eight branches should not be confused with the seven-branched menorah used in the ancient Temple and represented in Jewish symbolism. A Hanukkah lamp has eight holiday lights plus the shamash, making nine positions in all. On the final night, therefore, nine flames may be visible, but only eight are the commemorative Hanukkah lights.