SB 5.21.1

śrī-śuka uvāca
etāvān eva bhū-valayasya sanniveśaḥ pramāṇa-lakṣaṇato vyākhyātaḥ.
Word for word: 
śrī-śukaḥ uvāca — Śrī Śukadeva Gosvāmī said; etāvān — so much; eva — certainly; bhū-valayasya sanniveśaḥ — the arrangement of the whole universe; pramāṇa-lakṣaṇataḥ — according to measurement (fifty crores of yojanas, or four billion miles in width and length) and characteristics; vyākhyātaḥ — estimated.
Translation: 
Śukadeva Gosvāmī said: My dear King, I have thus far described the diameter of the universe [fifty crores of yojanas, or four billion miles] and its general characteristics, according to the estimations of learned scholars.