What is Ayaadi (Ayadi) Calculation in Vastu

What Ayaadi Is — and What It Is Not

Most modern Vastu analysis is about direction: which zone the kitchen falls in, where the entrance sits, how area distributes across the compass. Ayaadi is a different and older layer. It asks whether the proportions themselves are favourable, independent of where anything is placed.

The premise in the classical texts is that specific dimensional ratios resonate favourably while others do not, and that this can be tested arithmetically. The practical upshot for a builder is that two plots of nearly identical area can test very differently, and that small dimensional adjustments — a few inches on a wall — can change the result.

The Hasta: Why Units Matter

Ayaadi is not computed in feet or metres. Dimensions are first converted into a traditional unit — most commonly the hasta (cubit), historically about 24 inches but applied regionally at values ranging roughly from 21 to 33 inches depending on the tradition and the type of structure.

This is the most important practical detail in the entire calculation: the hasta value you choose changes the result. The formulae work on remainders, so converting 40 feet using a 33-inch hasta versus a 24-inch hasta produces different dimension values, different remainders and therefore different verdicts. Any Ayaadi calculation is only meaningful when the hasta value is stated alongside it.

The Shadvarga: Six Formulae

The classical set is called the Ayaadi Shadvarga — the six-fold Ayaadi. Each formula multiplies a dimension by one number, divides by another, and takes the remainder. The remainder is then looked up against a table of favourable and unfavourable values.

The divisors above are consistent across sources because they map onto real cycles — 27 nakshatras, 7 weekdays, 30 tithis, 8 directions. The multipliers and the input dimension, however, vary by text. Some traditions apply the formulae to the perimeter, others to the area, others to length and breadth separately.

This variation is genuine and documented — classical works including the Viswakarma Prakasika and Kalamruta set out the methods differently from one another. Anyone presenting a single set of multipliers as the only correct version is overstating the consensus. (Source content paraphrased for licensing compliance.)

Beyond the six: Amsha and Aayu

Although "shadvarga" means six-fold, most working implementations compute more than six. Two additions appear consistently:

• Amsha — indicates the nature of the land through the amsha lord of the navamsha rashi.
• Aayu — the longevity or beneficial life span associated with the built space.

Some classical treatments extend to nine or more vargas, adding factors such as Dhana and Rina. Our free Ayadi calculator returns eight: Aaya, Vyaya, Amsha, Nakshatra, Yoni, Vaara, Tithi and Aayu.

The most commonly cited forms

With that caveat stated, these are the versions cited most often in practice:

• Aaya = remainder of (dimension × 8) ÷ 12
• Vyaya = remainder of (dimension × 9) ÷ 10
• Yoni = remainder of (dimension × 3) ÷ 8
• Nakshatra = remainder of (dimension × 8) ÷ 27
• Vaara = remainder of (dimension × 9) ÷ 7
• Tithi = remainder of (dimension × 8) ÷ 30

The Central Rule: Aaya Must Exceed Vyaya

Of all the Ayaadi conditions, one is cited near-universally: Aaya (income) should be greater than Vyaya (expenditure).

The logic is transparently metaphorical — a structure whose numerical "income" exceeds its "expenditure" is considered to sustain itself, while the reverse is considered depleting. In practice this single comparison is often the first and sometimes the only Ayaadi check applied, and adjusting a dimension slightly to satisfy it is a standard move during design.

A secondary rule appearing in several sources: remainders of 0 are treated as unfavourable for most of the vargas, since a clean division is read as leaving nothing.

The Nakshatra Component

The Nakshatra varga produces a number from 0 to 26, mapping to one of the 27 lunar mansions. Two nakshatras usually matter in a full Ayaadi reading:

• The plot or building nakshatra — derived from the dimensions by the formula above.
• The owner's nakshatra — their birth star, from their birth details.

Classical practice then examines the relationship between the two. Certain pairings are considered compatible and others are not, following the same nakshatra-compatibility logic used elsewhere in Vedic astrology. This is why a complete Ayaadi calculation asks for the owner's birth star and not only the plot dimensions — the same plot can test differently for different owners.

The 27 nakshatras, in the order used for indexing:

A Worked Example

Take a plot measuring 40 feet × 30 feet, using a hasta of 33 inches.

1. Convert to inches: 40 ft = 480 in, 30 ft = 360 in.
2. Convert to hasta: 480 ÷ 33 ≈ 14.55 hasta; 360 ÷ 33 ≈ 10.91 hasta.
3. Derive the working dimension — perimeter or area depending on the tradition being followed. Perimeter in hasta ≈ 2 × (14.55 + 10.91) ≈ 50.9.
4. Apply each formula and take remainders. For Nakshatra: (50.9 × 8) ÷ 27 → 407.2 ÷ 27 = 15 remainder ≈ 2.2, indexing to a nakshatra near the start of the list.
5. Compare Aaya against Vyaya and check no varga returns a zero remainder.
6. Check the plot nakshatra against the owner's nakshatra for compatibility.

Two things become obvious from working through it by hand. First, the arithmetic is tedious and easy to slip on. Second, the result is highly sensitive to the hasta value — which is exactly why this is worth automating rather than doing on paper.

Using Ayaadi in Practice

Ayaadi is most useful at the two points where dimensions are still changeable:

• Choosing a plot. Run the check on shortlisted plots before purchase, alongside the plot-level factors in our Vastu check before buying a house guide.
• Fixing building dimensions. During design, adjust length and breadth slightly to satisfy the Aaya-over-Vyaya condition. Adjustments of a few inches are usually enough and cost nothing at the drawing stage.

It is far less useful after construction, because the dimensions are fixed and Ayaadi offers no remedies — unlike zone defects, which have non-demolition remedies. For an existing home, your effort is better spent on zone analysis.

Keeping It in Perspective

Ayaadi is a traditional proportional system, and the variation between classical texts is real rather than a matter of some sources being wrong. Treat it as one input among several, state the hasta value whenever you quote a result, and do not let a dimensional test override structural, legal or practical considerations about a property.