Using Lucy's birthyear of 1921 and subtracting from six to sixteen years, Ethel would have been born between 1905 and 1915. Her birthdate is never given, but she is a Leo, so her birthday must be sometime in late July or early-to-mid August.

How old was Ethel?

She is somewhere between 40 and 50 years old, around the same age Vivian Vance was in real life. So, Ethel is at least 7 years older than Lucy.

How old was Ethel when she died Lucy?

Vivian Vance, the Ethel Mertz of I Love Lucy and one of the most beloved comediennes in television, died Friday at her home in northern California after a long fight against cancer. She was 66.