Narada Purana (Jyotisha Selections) · by Vyasa
Chapter 9 · Vastu, Griha Pravesha
वास्तु गृहप्रवेशश्च
आरभ्य साधकं घिष्ण्यं साध्यं यावच्चतुर्गुणम् ।विभजेत्सप्तभिः शेषं साधकस्य धनं तदा ॥ ५६२ ॥
In the full Narada Purana (Purva Bhaga) this is chapter 56, verse 562.
Start from the nakshatra (star) of the sadhaka (the person seeking it). Count up to the nakshatra of the sadhya (the place sought). Multiply the count by four. Divide by seven. The remainder is the person's gain.
Simple meaning: Count the stars from the person to the place, multiply by four, divide by seven. The remainder shows gain.
विस्तार आयामगुणो गृहस्य पदमुच्यते ।
Multiply breadth by length to get the area. Six figures are worked out from it.
धनाधिकं गृहं वृद्ध्यै ऋणाधिकमशोभनम् ।
A house with more gain than debt is good. An odd aya point is good; an even one can bring poverty.
धनक्षयस्तृतीयर्क्षे पंचमर्क्षे परः क्षयः ।
From the owner's star, the house's 3rd star may cost wealth, the 5th more, the 7th risk the owner's life.