4BHK & Villa Interior Cost Calculator

How this calculator works

The arithmetic is four lines long and we publish all of it, so you can reconcile this number against any quotation you have been given.

1. Core cost = carpet area × finish rate × city factor × automation factor. The finish rate is the mid-point of the band for your finish level; the headline range is the band itself. Carpet area is the sum across every level, excluding the staircase footprint itself.
2. Extra bedrooms. Anything beyond the fourth bedroom adds a flat ₹2,90,000 — one wardrobe run, one bed-back unit, its ceiling and its share of the electrical distribution.
3. Staircase. ₹1,85,000 for a single flight with clad treads, a handrail and under-stair joinery; ₹3,40,000 where there are two flights or the stair is a designed feature with glass or metal fabrication.
4. Terrace and landscape. ₹2,50,000 for decking and planters; ₹6,00,000 for a full terrace garden with pergola, irrigation and lighting.
5. Range. The headline runs from the bottom to the top of the band for your finish level, with the staircase, terrace and extra-bedroom lines added flat at both ends because they do not move with the finish.

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Worked example — the default inputs

The calculator opens on a 2,200 sq ft four-bedroom villa in Mumbai at premium finish, with lighting and curtain automation, one internal staircase and a decked terrace. Following the formula above:

Where a villa budget actually goes

The percentage split in the breakdown is not a generic template. It comes from completed large-home projects, and it differs from a flat in three specific ways. Joinery is a larger share, because a villa has more wall length per square foot of floor once you count the passage, the landing and the second living area. Lighting is a larger share, because double-height volumes and stair wells need fittings that a 10 ft slab never does. And design and project management is 9% — the top of the 4–9% range we charge — rather than the 7% we use on a flat, because a villa runs six to eight months and the supervision is not optional.

What does not scale is the kitchen. A villa kitchen is bigger than a 2BHK kitchen but not proportionally — it is still one work triangle, one chimney and one set of appliances. It holds at 11% of the core here, the same share as in a flat, even though the rupee figure is two to three times larger. If a villa quote has the kitchen at 18% of the total, either the kitchen is exceptional or the rest of the house is under-specified.

The programme is the part people underestimate

A 2,200 sq ft villa is not a 2,200 sq ft flat with a staircase. The work happens on two or three levels, which means the same trade has to be mobilised twice, materials have to be carried up without a service lift in most gated developments, and the sequence has to be planned so that finished floors below are not damaged by work above. On our large-home projects the critical path is almost always joinery fabrication — eight to ten weeks in the factory before the first wardrobe reaches site — followed by the stone and the paint, which can only start once the joinery is in.

That is why design and project management is 9% of a villa budget rather than the 7% we apply to an apartment. Somebody has to be on site three days a week for six months, marking levels, checking that the electrician has not drilled through a conduit and confirming that the veneer delivered is the veneer approved. Where clients try to save that 2%, it reappears as rework, and rework on a villa is expensive because it is never in one room.

The other programme trap is the terrace. Deck laying cannot start until the waterproofing below it has been tested with a 48-hour ponding test, and that test cannot happen in the monsoon. If your handover is targeted for August, the deck is a September job whether the budget allows for it or not.

Every constant on this page comes from Greenbox site records — measured drawings, signed BOQs and final accounts on homes we have handed over — re-audited and restated at October 2026. We publish them so the arithmetic can be checked rather than trusted. Treat the output as a planning figure: accurate enough to brief a landlord, a bank or a family, and not accurate enough to sign a contract against.

What this tool does not cover

• Civil and structural work — internal walls, slab openings, waterproofing of the terrace deck and any change to the staircase geometry.
• Appliances, loose furniture, curtains, rugs and art, which on a villa of this size typically add ₹8–20 lakh.
• Compound work, boundary walls, gates, driveway paving and external façade treatment.
• Swimming pool, lift, DG set, solar and water treatment — all large-home items that belong in a separate services budget.
• Statutory approvals, architect's fees and any municipal permission for terrace structures.
• 18% GST, shown as a separate line in the breakdown.
• For a flat rather than a villa, the 3BHK calculator and the full interior cost calculator use apartment-scale assumptions.

Selected work by Greenbox Design Studio. Tap any image to enlarge.