A cubit is 1 1/2 feet, How long was the measuring reed?

Yes. A cubit is commonly reckoned as about 1½ feet, or 18 inches.

In Bible measurement, a cubit is generally the distance from a man’s elbow to the tip of his middle finger. So when studying Ezekiel’s temple measurements, using 1 cubit = 18 inches is a common and practical estimate.

One note: Ezekiel 40:5 mentions “a measuring reed of six cubits long by the cubit and an hand breadth,” which suggests a long cubit in Ezekiel’s temple vision—about 21 inches rather than 18 inches. So:

Common cubit: about 18 inches
Long cubit: about 21 inches

For Ezekiel 40–48, many conservative Bible students use the long cubit because of Ezekiel 40:5.

In Ezekiel 40:5, the measuring reed was:

“a measuring reed of six cubits long by the cubit and an hand breadth”

So the reed was six long cubits.

A common cubit is about 18 inches, and a handbreadth is about 3 inches, making Ezekiel’s “cubit and an hand breadth” about 21 inches.

So:

1 long cubit = about 21 inches
6 long cubits = 126 inches
126 inches = 10½ feet

So the measuring reed was approximately 10½ feet long.