Ezekiel 43:16
It was twenty-one feet square, wide and long.
Exodus 27:1
Build the altar with acacia wood. It should be seven and one half feet square and four and one half feet tall.
Exodus 38:1-2
He made the altar for burnt offerings out of acacia wood seven and one half feet square and four and one half feet high.
2 Chronicles 4:1
King Solomon had a copper altar built. It was thirty feet square and fifteen feet high.
Ezra 3:3
The returning exiles were afraid of the people who were living in the land. Regardless of that, they rebuilt the altar where it had stood before. Then they began once again to burn on it the regular morning and evening sacrifices.