When talking about measurements we are aware that the Rabbis over the centuries have debated the size of various measurements. To make things even more complicated the Talmud states that:-
אמת סוכה ואמת מבוי – באמה בת חמשה. אמת כלאים – באמה בת ששה
“The cubit [mentioned with regard to the halakhot] of sukka and the cubit [mentioned in connection with the halakhot] of an alleyway [is] a [small] cubit [consisting] of five [handbreadths. In contrast,] the cubit of [a forbidden mixture of] diverse kinds [of seeds is] a [large] cubit [consisting] of six [handbreadths.]
The koren notes:-
Since the measure of a cubit was originally based on the length of the forearm, i.e., the distance between the elbow and the tip of the middle finger, there was no single fixed measure. Not only were there cubits of five or six handbreadths, but there was even a distinction among as explained below, between those measured with expansive handbreadths and those measured with depressed ones. In the Temple, cubits slightly larger than six handbreadths were used.