Sri Lanka House Construction Cost Calculator

The calculator uses the per-square-foot method that Sri Lankan quantity surveyors and contractors use for early-stage budgeting. It multiplies your built-up floor area by a guideline all-in rate band, adjusts for the number of storeys, then splits the result across the standard cost heads. Because Sri Lankan building rates are market-driven — not a single gazetted figure — every output is a low–mid–high range, and the mid is the arithmetic midpoint of the band.

1. Rate band by finish grade. Each grade maps to a guideline rate range in Rs / sq ft:
   • Basic: Rs 5,000–6,500 / sq ft
   • Standard: Rs 6,500–8,500 / sq ft
   • Semi-luxury: Rs 9,000–12,000 / sq ft
   • Luxury: Rs 13,000–18,000 / sq ft
2. Storey factor. Multi-storey builds cost more per square foot. The applied factors are 1 storey ×1.00, 2 storey ×1.05, 3 storey ×1.10 — a quantity-surveying convention reflecting extra structure and stairs.
3. Core cost. For each of low, mid and high: cost = floor area × rate × storey factor. The mid rate is the midpoint of the band, so the mid cost is exactly the midpoint of the low and high costs — an internal cross-check the code verifies.
4. Cost-head split. The mid core cost is distributed across the CIDA Building Schedule of Rates elemental heads, which sum to 100%: substructure & foundation 12%, superstructure 28%, roofing 10%, finishes 30%, mep services 15%, external / site works 5%.
5. Optional external works. Toggling boundary wall + external works adds a guideline Rs 600–1,000 per square foot of floor area (a proxy for plot size), kept as a separate line so it never double-counts the house rate.
6. All figures are rounded to the nearest Rs 10,000 for display. The estimate excludes land, statutory approval fees, professional fees and price fluctuation over the build.

The rate bands are anchored to Q2 2026 (CIDA BSR / IQSSL prevailing rate bands)and drawn from CIDA's Building Schedule of Rates and the Institute of Quantity Surveyors Sri Lanka's prevailing per-square-foot ranges. This is a planning estimate: for a firm price, obtain a Bill of Quantities priced by a chartered quantity surveyor against your actual design and site.

• CIDA — Construction Industry Development Authority (Building Schedule of Rates)
• IQSSL — Institute of Quantity Surveyors Sri Lanka (prevailing per-sq-ft rate bands)
• Central Bank of Sri Lanka — construction and material price context

Rate bands were last reviewed against these sources on 2026-07-16, anchored to Q2 2026 (CIDA BSR / IQSSL prevailing rate bands). Per-square-foot rates are guideline market bands, not a gazetted figure — obtain a Bill of Quantities from a chartered quantity surveyor for a firm price.